There are a variety of different kinds of free online shopping carts. Some are also open source meaning that you have full access to the code and can edit it. Some free carts also include free hosting, these are usually carts that are very limited where they are hoping you will eventually upgrade to a paid plan. Some of the free carts require a link back to their website
Downloadable free shopping carts must be downloaded and then installed on a ecommerce host.
URL: http://www.woothemes.com/woocommerce/
Type: WordPress Shopping Cart Plugin
Review: WooCommerce Review
URL: http://www.nopdesign.com/freecart/
Type: Javascript
URL: http://www.commerce-cgi.com/
Type: CGI
URL: http://www.shop-script.com/scripts/shop-script-free.html
Type: PHP
Type: PHP (Community version)
URL: http://www.tomatocart.com
Type: PHP (Community Edition)
Type: PHP (Free version)
Type: ASP (Free version)
Hosted stand-alone shopping carts can be used on their own without an existing website. These carts do not require separate hosting or installation.
URL: http://www.1freecart.com/
Type: Ad Supported
Hosted add-on shopping carts are meant to be added onto an existing website. They usually provide html code that will make an add to cart button.
URL: http://www.fatfreecart.com/
Open source ecommerce tools are supported by a community instead of a company. They are free tools and you have full access to the original source code which you can modify. Open source projects require ecommerce hosting.
Type: PHP
URL: http://www.agoracart.com/
Type: PHP
URL: http://www.litecommerce.com/
Type: PHP
URL: http://www.prestashop.com/
Type: PHP
URL: http://www.magentocommerce.com
Type: PHP (Community Edition)
URL: http://www.oscommerce.com/
Type: PHP
Read about the hidden costs of open source ecommerce.