OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s
HelpNDoc - What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.
WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.
Dr.Explain - Dr.Explain software is a help file authoring tool.
PrestaShop - Create your online store with PrestaShop's free shopping cart software. Build an ecommerce website for free and start selling online with hundreds of powerful features.
CHM Editor - Best solution to edit CHM files