diff --git a/app.py b/app.py
new file mode 100644
index 0000000..a993544
--- /dev/null
+++ b/app.py
@@ -0,0 +1,184 @@
+import sqlite3
+from datetime import datetime
+import os
+
+DB_PATH = "grocery_receipts.db"
+
+def init_db():
+    """Initialize the database with required tables."""
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+    
+    # Create stores table
+    cursor.execute('''
+        CREATE TABLE IF NOT EXISTS stores (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            name TEXT NOT NULL UNIQUE
+        )
+    ''')
+    
+    # Create products table
+    cursor.execute('''
+        CREATE TABLE IF NOT EXISTS products (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            name TEXT NOT NULL UNIQUE
+        )
+    ''')
+    
+    # Create receipts table
+    cursor.execute('''
+        CREATE TABLE IF NOT EXISTS receipts (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            store_id INTEGER NOT NULL,
+            date DATE NOT NULL,
+            total REAL NOT NULL,
+            FOREIGN KEY (store_id) REFERENCES stores(id)
+        )
+    ''')
+    
+    # Create receipt_items table (linking products to receipts with prices)
+    cursor.execute('''
+        CREATE TABLE IF NOT EXISTS receipt_items (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            receipt_id INTEGER NOT NULL,
+            product_id INTEGER NOT NULL,
+            quantity REAL NOT NULL,
+            price REAL NOT NULL,
+            FOREIGN KEY (receipt_id) REFERENCES receipts(id),
+            FOREIGN KEY (product_id) REFERENCES products(id)
+        )
+    ''')
+    
+    conn.commit()
+    conn.close()
+
+def add_receipt(store_name, date, items):
+    """
+    Add a receipt to the database.
+    
+    Args:
+        store_name: Name of the store
+        date: Date of the receipt (YYYY-MM-DD format)
+        items: List of tuples (product_name, quantity, price_per_unit)
+    """
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+    
+    # Get or create store
+    cursor.execute("SELECT id FROM stores WHERE name = ?", (store_name,))
+    store = cursor.fetchone()
+    if not store:
+        cursor.execute("INSERT INTO stores (name) VALUES (?)", (store_name,))
+        conn.commit()
+        cursor.execute("SELECT id FROM stores WHERE name = ?", (store_name,))
+        store = cursor.fetchone()
+    
+    store_id = store[0]
+    
+    # Insert receipt
+    cursor.execute("INSERT INTO receipts (store_id, date, total) VALUES (?, ?, ?)",
+                   (store_id, date, sum(item[1] * item[2] for item in items)))
+    receipt_id = cursor.lastrowid
+    
+    # Insert items
+    for product_name, quantity, price in items:
+        # Get or create product
+        cursor.execute("SELECT id FROM products WHERE name = ?", (product_name,))
+        product = cursor.fetchone()
+        if not product:
+            cursor.execute("INSERT INTO products (name) VALUES (?)", (product_name,))
+            conn.commit()
+            cursor.execute("SELECT id FROM products WHERE name = ?", (product_name,))
+            product = cursor.fetchone()
+        
+        product_id = product[0]
+        cursor.execute("INSERT INTO receipt_items (receipt_id, product_id, quantity, price) VALUES (?, ?, ?, ?)",
+                       (receipt_id, product_id, quantity, price))
+    
+    conn.commit()
+    conn.close()
+
+def get_product_prices(product_name):
+    """
+    Get all prices for a specific product across all receipts.
+    
+    Args:
+        product_name: Name of the product
+        
+    Returns:
+        List of tuples (date, store_name, quantity, price_per_unit)
+    """
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+    
+    cursor.execute('''
+        SELECT r.date, s.name, ri.quantity, ri.price
+        FROM receipt_items ri
+        JOIN receipts r ON ri.receipt_id = r.id
+        JOIN stores s ON r.store_id = s.id
+        JOIN products p ON ri.product_id = p.id
+        WHERE p.name = ?
+        ORDER BY r.date
+    ''', (product_name,))
+    
+    results = cursor.fetchall()
+    conn.close()
+    
+    return results
+
+def list_receipts():
+    """
+    List all receipts in the database.
+    
+    Returns:
+        List of tuples (receipt_id, store_name, date, total)
+    """
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+    
+    cursor.execute('''
+        SELECT r.id, s.name, r.date, r.total
+        FROM receipts r
+        JOIN stores s ON r.store_id = s.id
+        ORDER BY r.date DESC
+    ''')
+    
+    results = cursor.fetchall()
+    conn.close()
+    
+    return results
+
+# Initialize the database when the module is imported
+init_db()
+
+if __name__ == "__main__":
+    # Example usage
+    print("Grocery Receipt Tracker - Demo")
+    print("=" * 30)
+    
+    # Add a sample receipt
+    items = [
+        ("Milk", 2, 1.50),
+        ("Bread", 1, 2.00),
+        ("Apples", 3, 0.80)
+    ]
+    add_receipt("SuperMarket", "2023-10-15", items)
+    print("Added sample receipt to database.")
+    
+    # Add another receipt for comparison
+    items2 = [
+        ("Milk", 1, 1.30),
+        ("Bread", 1, 1.80)
+    ]
+    add_receipt("Corner Store", "2023-10-20", items2)
+    print("Added another receipt to database.")
+    
+    # Show all receipts
+    print("\nAll Receipts:")
+    for receipt in list_receipts():
+        print(f"  ID: {receipt[0]}, Store: {receipt[1]}, Date: {receipt[2]}, Total: ${receipt[3]:.2f}")
+    
+    # Show prices for a specific product
+    print("\nMilk Prices Over Time:")
+    for price_info in get_product_prices("Milk"):
+        print(f"  Date: {price_info[0]}, Store: {price_info[1]}, Qty: {price_info[2]}, Price: ${price_info[3]:.2f}")
diff --git a/requirements.txt b/requirements.txt
index e69de29..c737efd 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -0,0 +1,2 @@
+# No external dependencies required for this SQLite-based implementation
+# Python standard library is sufficient for the core functionality