diff --git a/packages/core/src/builder/outputBuilder.ts b/packages/core/src/builder/outputBuilder.ts
index 742c6b06..86659b57 100644
--- a/packages/core/src/builder/outputBuilder.ts
+++ b/packages/core/src/builder/outputBuilder.ts
@@ -23,7 +23,7 @@ import { InvalidRegistersPacking } from "../errors/invalidRegistersPacking";
 import { UndefinedCreationHeight } from "../errors/undefinedCreationHeight";
 import { UndefinedMintingContext } from "../errors/undefinedMintingContext";
 import { ErgoAddress } from "../models";
-import { AddTokenOptions, TokensCollection } from "../models/collections/tokensCollection";
+import { TokenAddOptions, TokensCollection } from "../models/collections/tokensCollection";
 import { SConstant } from "../serialization/sigma/constantSerializer";
 import { SByte, SColl } from "../serialization/sigma/sigmaTypes";
 
@@ -86,7 +86,7 @@ export class OutputBuilder {
 
   public addTokens(
     tokens: TokenAmount<Amount>[] | TokenAmount<Amount> | TokensCollection,
-    options?: AddTokenOptions
+    options?: TokenAddOptions
   ) {
     if (tokens instanceof TokensCollection) {
       this._tokens.add(tokens.toArray(), options);
diff --git a/packages/core/src/builder/transactionBuilder.ts b/packages/core/src/builder/transactionBuilder.ts
index 8d05dc5f..9685971c 100644
--- a/packages/core/src/builder/transactionBuilder.ts
+++ b/packages/core/src/builder/transactionBuilder.ts
@@ -22,13 +22,8 @@ import {
 } from "@fleet-sdk/common";
 import { InvalidInput, MalformedTransaction, NotAllowedTokenBurning } from "../errors";
 import { NonStandardizedMinting } from "../errors/nonStandardizedMinting";
-import {
-  AddOutputOptions,
-  ErgoAddress,
-  InputsCollection,
-  OutputsCollection,
-  TokensCollection
-} from "../models";
+import { ErgoAddress, InputsCollection, OutputsCollection, TokensCollection } from "../models";
+import { CollectionAddOptions } from "../models/collections/collection";
 import { OutputBuilder, SAFE_MIN_BOX_VALUE } from "./outputBuilder";
 import { BoxSelector } from "./selector";
 import { TransactionBuilderSettings } from "./transactionBuilderSettings";
@@ -117,23 +112,29 @@ export class TransactionBuilder {
     return this;
   }
 
-  public from(inputs: Box<Amount> | Box<Amount>[]): TransactionBuilder {
-    this._inputs.add(inputs);
+  public from(
+    inputs: Box<Amount> | Box<Amount>[],
+    options?: CollectionAddOptions
+  ): TransactionBuilder {
+    this._inputs.add(inputs, options);
 
     return this;
   }
 
   public to(
     outputs: OutputBuilder[] | OutputBuilder,
-    options?: AddOutputOptions
+    options?: CollectionAddOptions
   ): TransactionBuilder {
     this._outputs.add(outputs, options);
 
     return this;
   }
 
-  public withDataFrom(dataInputs: Box<Amount>[] | Box<Amount>): TransactionBuilder {
-    this._dataInputs.add(dataInputs);
+  public withDataFrom(
+    dataInputs: Box<Amount>[] | Box<Amount>,
+    options?: CollectionAddOptions
+  ): TransactionBuilder {
+    this._dataInputs.add(dataInputs, options);
 
     return this;
   }
diff --git a/packages/core/src/models/collections/collection.spec.ts b/packages/core/src/models/collections/collection.spec.ts
index 56825d0d..a5d67c55 100644
--- a/packages/core/src/models/collections/collection.spec.ts
+++ b/packages/core/src/models/collections/collection.spec.ts
@@ -5,10 +5,8 @@ class MockCollection extends Collection<number, number> {
     super();
   }
 
-  protected override _addOne(numb: number) {
-    this._items.push(numb);
-
-    return this.length;
+  protected override _map(item: number): number {
+    return item;
   }
 
   public remove(item: number): number {
@@ -25,6 +23,65 @@ describe("collection base", () => {
     expect(collection.isEmpty).toBeTruthy();
   });
 
+  it("Should add items", () => {
+    const collection = new MockCollection();
+    collection.add(1);
+    collection.add([2, 3]);
+
+    expect(collection).toHaveLength(3);
+    expect(collection.at(0)).toBe(1);
+    expect(collection.at(1)).toBe(2);
+    expect(collection.at(2)).toBe(3);
+  });
+
+  it("Should place one item at a specific index", () => {
+    const collection = new MockCollection();
+    collection.add([1, 2, 3]);
+
+    collection.add(5, { index: 0 });
+
+    expect(collection).toHaveLength(4);
+    expect(collection.at(0)).toBe(5);
+    expect(collection.at(1)).toBe(1);
+    expect(collection.at(2)).toBe(2);
+    expect(collection.at(3)).toBe(3);
+  });
+
+  it("Should not fail when trying to place at index 0 and collection is empty", () => {
+    const collection = new MockCollection();
+
+    collection.add(5, { index: 0 });
+
+    expect(collection).toHaveLength(1);
+    expect(collection.at(0)).toBe(5);
+  });
+
+  it("Should should fail when trying to add out of range", () => {
+    const collection = new MockCollection();
+
+    expect(() => {
+      collection.add(5, { index: 1 });
+    }).toThrow(RangeError);
+
+    expect(() => {
+      collection.add(5, { index: 2 });
+    }).toThrow(RangeError);
+  });
+
+  it("Should place multiple items at a specific index", () => {
+    const collection = new MockCollection();
+    collection.add([1, 2, 3]);
+
+    collection.add([10, 20], { index: 2 });
+
+    expect(collection).toHaveLength(5);
+    expect(collection.at(0)).toBe(1);
+    expect(collection.at(1)).toBe(2);
+    expect(collection.at(2)).toBe(10);
+    expect(collection.at(3)).toBe(20);
+    expect(collection.at(4)).toBe(3);
+  });
+
   it("Should create a copy of the internal array", () => {
     const collection = new MockCollection();
     collection.add(numbers);
diff --git a/packages/core/src/models/collections/collection.ts b/packages/core/src/models/collections/collection.ts
index a831b476..991c52f3 100644
--- a/packages/core/src/models/collections/collection.ts
+++ b/packages/core/src/models/collections/collection.ts
@@ -1,3 +1,7 @@
+import { isDefined } from "@fleet-sdk/common";
+
+export type CollectionAddOptions = { index?: number };
+
 export abstract class Collection<InternalType, ExternalType> implements Iterable<InternalType> {
   protected readonly _items: InternalType[];
 
@@ -38,16 +42,45 @@ export abstract class Collection<InternalType, ExternalType> implements Iterable
     return this._items[index];
   }
 
-  public add(items: ExternalType[] | ExternalType): number {
-    return this._addOneOrMore(items);
+  public add(items: ExternalType[] | ExternalType, options?: CollectionAddOptions): number {
+    return this._addOneOrMore(items, options);
   }
 
   abstract remove(item: unknown): number;
 
-  protected abstract _addOne(item: ExternalType, options?: unknown): number;
+  protected abstract _map(item: ExternalType | InternalType): InternalType;
+
+  protected _addOne(item: InternalType | ExternalType, options?: CollectionAddOptions): number {
+    if (isDefined(options) && isDefined(options.index)) {
+      if (options.index === 0 && this.length === 0) {
+        this._items.push(this._map(item));
+
+        return this.length;
+      }
+
+      if (this._isIndexOutOfBounds(options.index)) {
+        throw new RangeError(`Index '${options.index}' is out of range.`);
+      }
+
+      this._items.splice(options.index, 0, this._map(item));
 
-  protected _addOneOrMore(items: ExternalType[] | ExternalType, options?: unknown): number {
+      return this.length;
+    }
+
+    this._items.push(this._map(item));
+
+    return this._items.length;
+  }
+
+  protected _addOneOrMore(
+    items: ExternalType[] | ExternalType,
+    options?: CollectionAddOptions
+  ): number {
     if (Array.isArray(items)) {
+      if (isDefined(options) && isDefined(options.index)) {
+        items = items.reverse();
+      }
+
       for (const item of items) {
         this._addOne(item, options);
       }
diff --git a/packages/core/src/models/collections/inputsCollection.ts b/packages/core/src/models/collections/inputsCollection.ts
index b34bd6b0..eae4ddb4 100644
--- a/packages/core/src/models/collections/inputsCollection.ts
+++ b/packages/core/src/models/collections/inputsCollection.ts
@@ -16,14 +16,16 @@ export class InputsCollection extends Collection<ErgoUnsignedInput, Box<Amount>>
     }
   }
 
+  protected override _map(input: Box<Amount> | ErgoUnsignedInput): ErgoUnsignedInput {
+    return input instanceof ErgoUnsignedInput ? input : new ErgoUnsignedInput(input);
+  }
+
   protected override _addOne(box: Box<Amount>): number {
     if (this._items.some((item) => item.boxId === box.boxId)) {
       throw new DuplicateInputError(box.boxId);
     }
 
-    this._items.push(box instanceof ErgoUnsignedInput ? box : new ErgoUnsignedInput(box));
-
-    return this._items.length;
+    return super._addOne(box);
   }
 
   public remove(boxId: BoxId): number;
diff --git a/packages/core/src/models/collections/outputsCollection.ts b/packages/core/src/models/collections/outputsCollection.ts
index 5ee3fc99..84de4262 100644
--- a/packages/core/src/models/collections/outputsCollection.ts
+++ b/packages/core/src/models/collections/outputsCollection.ts
@@ -4,8 +4,6 @@ import { SelectionTarget } from "../../builder/selector/boxSelector";
 import { NotFoundError } from "../../errors";
 import { Collection } from "./collection";
 
-export type AddOutputOptions = { index: number };
-
 export class OutputsCollection extends Collection<OutputBuilder, OutputBuilder> {
   constructor(outputs?: OutputBuilder | OutputBuilder[]) {
     super();
@@ -15,29 +13,8 @@ export class OutputsCollection extends Collection<OutputBuilder, OutputBuilder>
     }
   }
 
-  protected override _addOne(output: OutputBuilder, options?: AddOutputOptions): number {
-    if (isDefined(options) && isDefined(options.index)) {
-      if (this._isIndexOutOfBounds(options.index)) {
-        throw new RangeError(`Index '${options.index}' is out of range.`);
-      }
-
-      this._items.splice(options.index, 0, output);
-    } else {
-      this._items.push(output);
-    }
-
-    return this._items.length;
-  }
-
-  public override add(
-    outputs: OutputBuilder | OutputBuilder[],
-    options?: AddOutputOptions
-  ): number {
-    if (Array.isArray(outputs) && isDefined(options) && isDefined(options.index)) {
-      return this._addOneOrMore(outputs.reverse(), options);
-    }
-
-    return this._addOneOrMore(outputs, options);
+  protected _map(output: OutputBuilder): OutputBuilder {
+    return output;
   }
 
   public remove(output: OutputBuilder): number;
diff --git a/packages/core/src/models/collections/tokensCollection.spec.ts b/packages/core/src/models/collections/tokensCollection.spec.ts
index ab4a06ca..39c9c917 100644
--- a/packages/core/src/models/collections/tokensCollection.spec.ts
+++ b/packages/core/src/models/collections/tokensCollection.spec.ts
@@ -92,12 +92,40 @@ describe("Tokens collection", () => {
     expect(collection.toArray().find((x) => x.tokenId === tokenA)?.amount).toEqual(50n);
 
     collection.add({ tokenId: tokenA, amount: 100n }, { sum: true });
+
     expect(collection).toHaveLength(2);
     const tokensArray = collection.toArray();
     expect(tokensArray.find((x) => x.tokenId === tokenA)?.amount).toEqual(150n);
     expect(tokensArray.find((x) => x.tokenId === tokenB)?.amount).toEqual(10n);
   });
 
+  it("Should not sum if the same tokenId is already included but index is set", () => {
+    const collection = new TokensCollection();
+    collection.add({ tokenId: tokenA, amount: 50n });
+    collection.add({ tokenId: tokenB, amount: 10n });
+
+    collection.add({ tokenId: tokenA, amount: 100n }, { sum: true, index: 1 });
+
+    expect(collection).toHaveLength(3);
+    expect(collection.at(0).tokenId).toBe(tokenA);
+    expect(collection.at(1).tokenId).toBe(tokenA);
+    expect(collection.at(2).tokenId).toBe(tokenB);
+  });
+
+  it("Should place token item at specific index", () => {
+    const collection = new TokensCollection();
+    collection.add({ tokenId: tokenA, amount: 50n });
+    collection.add({ tokenId: tokenB, amount: 10n });
+
+    collection.add({ tokenId: tokenB, amount: 100n }, { index: 1 });
+
+    expect(collection).toHaveLength(3);
+
+    expect(collection.at(0).tokenId).toBe(tokenA);
+    expect(collection.at(1).tokenId).toBe(tokenB);
+    expect(collection.at(2).tokenId).toBe(tokenB);
+  });
+
   it("Should add if sum = false if tokenId is already included", () => {
     const collection = new TokensCollection();
     collection.add({ tokenId: tokenA, amount: 50n });
diff --git a/packages/core/src/models/collections/tokensCollection.ts b/packages/core/src/models/collections/tokensCollection.ts
index 7fe25f8d..016a1d71 100644
--- a/packages/core/src/models/collections/tokensCollection.ts
+++ b/packages/core/src/models/collections/tokensCollection.ts
@@ -3,18 +3,18 @@ import { ensureBigInt } from "@fleet-sdk/common";
 import { NotFoundError } from "../../errors";
 import { InsufficientTokenAmount } from "../../errors/insufficientTokenAmount";
 import { MaxTokensOverflow } from "../../errors/maxTokensOverflow";
-import { Collection } from "./collection";
+import { Collection, CollectionAddOptions } from "./collection";
 
 export const MAX_TOKENS_PER_BOX = 120;
 
-export type AddTokenOptions = { sum: boolean };
+export type TokenAddOptions = CollectionAddOptions & { sum?: boolean };
 
 export class TokensCollection extends Collection<TokenAmount<bigint>, TokenAmount<Amount>> {
   constructor();
   constructor(token: TokenAmount<Amount>);
   constructor(tokens: TokenAmount<Amount>[]);
-  constructor(tokens: TokenAmount<Amount>[], options: AddTokenOptions);
-  constructor(tokens?: TokenAmount<Amount> | TokenAmount<Amount>[], options?: AddTokenOptions) {
+  constructor(tokens: TokenAmount<Amount>[], options: TokenAddOptions);
+  constructor(tokens?: TokenAmount<Amount> | TokenAmount<Amount>[], options?: TokenAddOptions) {
     super();
 
     if (isDefined(tokens)) {
@@ -22,14 +22,17 @@ export class TokensCollection extends Collection<TokenAmount<bigint>, TokenAmoun
     }
   }
 
-  protected override _addOne(token: TokenAmount<Amount>, options?: AddTokenOptions): number {
-    if (!options || isUndefined(options.sum) || options.sum === true) {
-      for (const t of this._items) {
-        if (t.tokenId === token.tokenId) {
-          t.amount += ensureBigInt(token.amount);
+  protected override _map(token: TokenAmount<bigint> | TokenAmount<Amount>): TokenAmount<bigint> {
+    return { tokenId: token.tokenId, amount: ensureBigInt(token.amount) };
+  }
 
-          return this.length;
-        }
+  protected override _addOne(
+    token: TokenAmount<bigint> | TokenAmount<Amount>,
+    options?: TokenAddOptions
+  ): number {
+    if (isUndefined(options) || (options.sum && !isDefined(options.index))) {
+      if (this._sum(this._map(token))) {
+        return this.length;
       }
     }
 
@@ -37,16 +40,28 @@ export class TokensCollection extends Collection<TokenAmount<bigint>, TokenAmoun
       throw new MaxTokensOverflow();
     }
 
-    this._items.push({ tokenId: token.tokenId, amount: ensureBigInt(token.amount) });
+    super._addOne(token, options);
 
     return this.length;
   }
 
   public override add(
     items: TokenAmount<Amount> | TokenAmount<Amount>[],
-    options?: AddTokenOptions
+    options?: TokenAddOptions
   ): number {
-    return super._addOneOrMore(items, options);
+    return super.add(items, options);
+  }
+
+  private _sum(token: TokenAmount<bigint>): boolean {
+    for (const t of this._items) {
+      if (t.tokenId === token.tokenId) {
+        t.amount += token.amount;
+
+        return true;
+      }
+    }
+
+    return false;
   }
 
   public remove(tokenId: TokenId, amount?: Amount): number;