Your shopping cart system is the heart of your ecommerce site. Select it first and then identify which databases, Web hosts, and payment options will support it. Packaged systems range in price from free to several thousand dollars. Here is just a sample for price comparison only. NetMechanic isn't recommending or endorsing any of these systems.
Prices depend on what functions and capabilities the systems provide.
Pricier isn't always better. If you need a very basic shopping cart system to sell just a few products, then one of the simpler systems will suit your needs just fine. You may even be able to get by with a free system. The Online Orders Web site has a section that briefly discusses the capabilities of 40 free shopping cart programs and contains a link to each product's Web site. The quality and reliability of free systems varies from product to product, as does the technical support available.