MarketPress Lite – WordPress eCommerce is an e-commerce plugin by WPMUDEV and uglyrobot designed from the ground up for seamless integration with WP Multisite and BuddyPress.
Some MarketPress Features:
Simple product thumbnails/images with lightbox zooming
Add temporary sale prices
Downloadable/digital products with limits and tracking – Premium Version only!
Unlimited product variations
Stock tracking and alerts per variation
Per order product limits
AJAX cart and cart widget
Powerful widgets and shortcodes for displaying your products just how you want
Link a product to an external link (for affiliate commissions, etc). You can also turn off all checkout features and use MarketPress as a listing plugin only, generating revenue from affiliate commissions on sites like ClickBank, E-junkie or Amazon Affiliate.
Assign categories and tags to products to make them easy to find
Stock tracking with alerts
Fully customizable email messages
Full support for most major currencies
Flexible sales tax/VAT options
Full coupon/discount support. Create coupon codes for percentage or amount off, and control and track their usage date range and/or maximum uses – Premium Version only!.
3 built-in css themes designed to work within your site theme – Premium Version only!
Fully customizable store urls/slugs
Customers can checkout without being a site user
Order status tracking for customers on the front end. Previous orders are stored in a cookie and/or user meta.
More quality features than any other WordPress e-commerce plugin.
Multiple payment gateways – Premium Version only!
MarketPress Lite is a fully functional but they is a premium version, with additional features:
Product downloads – sell digital goods!
Powerful coupon codes for your store with usage tracking and limits
Access to all gateways including: 2Checkout, Authorize.NET AIM, Google Checkout, Moneybookers, and PayPal chained payments
More built-in themes, or add your own simple CSS based themes
Multisite marketplace features – product lists, tags, categories, widgets, and shortcodes
Charge for store upgrades like themes and gateways with our Supporter plugin
Global Shopping Carts
Ability for Network owner to take a percentage of each marketplace sale through the PayPal chained payment gateway
Download and info: http://wordpress.org/extend/plugins/wordpress-ecommerce/