@@ -0,0 +1,152 @@
+package store.domain;
+
+import static store.constants.ReceiptConstants.EVENT_DISCOUNT;
+import static store.constants.ReceiptConstants.FINAL_AMOUNT;
+import static store.constants.ReceiptConstants.LINE_SEPARATOR;
+import static store.constants.ReceiptConstants.MEMBERSHIP_DISCOUNT;
+import static store.constants.ReceiptConstants.ORDER_DETAIL_FORMAT;
+import static store.constants.ReceiptConstants.PRICE;
+import static store.constants.ReceiptConstants.PRODUCT_HEADER;
+import static store.constants.ReceiptConstants.PRODUCT_NAME;
+import static store.constants.ReceiptConstants.PROMOTION_DETAIL_FORMAT;
+import static store.constants.ReceiptConstants.PROMOTION_HEADER;
+import static store.constants.ReceiptConstants.QUANTITY;
+import static store.constants.ReceiptConstants.RECEIPT_HEADER;
+import static store.constants.ReceiptConstants.TOTAL_DETAIL_FORMAT;
+import static store.constants.ReceiptConstants.TOTAL_PURCHASE_AMOUNT;
+
+import java.text.NumberFormat;
+import java.util.Locale;
+
+public class Receipt {
+    private final Store store;
+    private final Cart cart;
+    private final Membership membership;
+
+    public Receipt(Store store, Cart cart, Membership membership) {
+        this.store = store;
+        this.cart = cart;
+        this.membership = membership;
+    }
+
+    @Override
+    public String toString() {
+        return buildReceiptContent();
+    }
+
+    public boolean hasFreeItems() {
+        return cart.getTotalFreeItemQuantity() > 0;
+    }
+
+    /**
+     * 장바구니 및 멤버십 정보를 바탕으로 영수증 내용을 빌드하는 메서드입니다.
+     * <p>
+     * 추가로 증정된 상품이 없다면 상품내역 정보는 출력하지 않습니다.
+     */
+    public String buildReceiptContent() {
+        StringBuilder result = new StringBuilder();
+        result.append(getReceiptHeader());
+        result.append(toStringOrderDetail());
+        if (hasFreeItems()) {
+            result.append(toStringRemainingItemsForPromotion());
+        }
+        result.append(toStringTotal());
+        return result.toString();
+    }
+
+    /**
+     * 영수증 헤더를 반환하는 메서드입니다.
+     */
+    public String getReceiptHeader() {
+        StringBuilder header = new StringBuilder();
+        header.append(RECEIPT_HEADER).append("\n");
+        header.append(String.format(PRODUCT_HEADER, PRODUCT_NAME, QUANTITY, PRICE)).append("\n");
+        return header.toString();
+    }
+
+    /**
+     * 주문 내역을 문자열로 반환하는 메서드입니다.
+     */
+    public String toStringOrderDetail() {
+        StringBuilder orderDetail = new StringBuilder();
+
+        for (CartItem cartItem : cart.getAllItemsInCart()) {
+            orderDetail.append(String.format(ORDER_DETAIL_FORMAT, cartItem.getProductName(),
+                            numberFormat(cartItem.getQuantity()), numberFormat(cartItem.totalPrice())))
+                    .append("\n");
+        }
+        return orderDetail.toString();
+    }
+
+    /**
+     * 증정 상품 내역을 문자열로 반환하는 메서드입니다.
+     */
+    public String toStringRemainingItemsForPromotion() {
+        StringBuilder remainingitems = new StringBuilder();
+        remainingitems.append(PROMOTION_HEADER).append("\n");
+
+        for (CartItem cartItem : cart.getAllItemsInCart()) {
+            if (cartItem.getFreeQuantity() > 0) {
+                remainingitems.append(String.format(PROMOTION_DETAIL_FORMAT, cartItem.getProductName(),
+                                numberFormat(cartItem.getFreeQuantity())))
+                        .append("\n");
+            }
+        }
+        return remainingitems.toString();
+    }
+
+    /**
+     * 총 금액 내역을 문자열로 반환하는 메서드입니다.
+     */
+    public String toStringTotal() {
+        StringBuilder total = new StringBuilder();
+        total.append(LINE_SEPARATOR).append("\n");
+
+        total.append(formatTotalItemPrice())
+                .append("\n");
+        total.append(formatEventDiscount())
+                .append("\n");
+        total.append(formatMembershipDiscount())
+                .append("\n");
+        total.append(formatFinalAmount())
+                .append("\n");
+
+        return total.toString();
+    }
+
+    /**
+     * 총 구매 금액을 포맷팅하여 반환
+     */
+    public String formatTotalItemPrice() {
+        return String.format(TOTAL_DETAIL_FORMAT, TOTAL_PURCHASE_AMOUNT, numberFormat(cart.getTotalItemPrice()));
+    }
+
+    /**
+     * 이벤트 할인 금액을 포맷팅하여 반환
+     */
+    public String formatEventDiscount() {
+        return String.format(TOTAL_DETAIL_FORMAT, EVENT_DISCOUNT, numberFormat(cart.getTotalFreeItemPrice()));
+    }
+
+    /**
+     * 멤버십 할인 금액을 포맷팅하여 반환
+     */
+    public String formatMembershipDiscount() {
+        return String.format(TOTAL_DETAIL_FORMAT, MEMBERSHIP_DISCOUNT, numberFormat(membership.getMembershipPrice()));
+    }
+
+    /**
+     * 최종 금액을 포맷팅하여 반환
+     */
+    public String formatFinalAmount() {
+        int finalAmount = cart.getTotalItemPrice() - cart.getTotalFreeItemPrice() - membership.getMembershipPrice();
+        return String.format(TOTAL_DETAIL_FORMAT, FINAL_AMOUNT, numberFormat(finalAmount));
+    }
+
+    /**
+     * 숫자를 한국의 숫자 포맷에 맞게 형식화하는 메서드입니다.
+     */
+    public String numberFormat(int number) {
+        return NumberFormat.getInstance(Locale.KOREA).format(number);
+    }
+}

리뷰: 함수형 인터페이스도 depth가 있다고 생각합니다!
모듈화를 해보는건 어떨까요?