OpenCart lets you create unlimited categories for your products, support multiple currencies, allow product reviews and ratings, which can be useful if you're selling products from different manufacturers (think Amazon), sell downloadable goods (like ebooks and software), set multiple tax rates, display related products, issue discount coupons, give your customers printable invoices, calculate shipping, etc. It is available in many languages and support a wide variety of payment options.
Features:
Adminstrator Dashboard User Management Multiple Stores Unlimited Categories Unlimited Products Multi-Currency Multi-Lingual Sales Reports Third Party Extensions