Products Manager + Button-Wiz + IPN is an excellent ecommerce software package that allow users to manage full featured online shopping system. Using this script users can create product catalogs with categories and sub categories, set affiliate commissions, accept online payments through Paypal's IPN integration, send emails to customers regarding the sales etc,. This software can automatically handle sales orders for all products, caters for products price-changes and also provides system stats pages for every products.