MARKETPRESS is the easiest to use, best designed and most powerful ecommerce / shopping cart plugin available for WordPress today. Developed from the ground up to make it simple to set up a stylish online shop, MarketPress has all the features you need, including:

• Multiple payment gateways (PayPal Express Checkout, Authorize.net AIM, Google checkout, 2checkout, Moneybookers, eWay shared payments, Cubepoints and more)
• Works great with any WordPress theme and looks great with AJAXy goodness
• Fully internationalized by the WPML crew
• Sell real objects, or digital downloads (with limits and tracking!), with ease
• Shipping, coupons, Google Analytics eCommerce, sales pricing, unlimited product variations, and so so much more!