You basically have two choices, paid for or open source

• Paid is easier to setup and manage and generally has the best feature set
• Free is harder to manage, design and upkeep

Why Shopping Cart Software?

Don't let the name fool you; shopping cart software is a lot more than just a payment gateway service. Good shopping cart software offers a host of other tools to help get your online business up and running. Here are just some of the ways in which comprehensive shopping cart software can help your business:

Payment Processing – Many shopping cart programs offer credit card processing as well as check, PayPal or other methods of processing payments.

Webpage Design – Many merchants are good at selling things, not designing webpages, so some shopping cart software will include step-by-step wizards to help take the mystery out of that process – you don’t even have to know HTML.

Storefront Design – Step-by-step store front wizards incorporate templates and other tools to help you set up the look of your website’s storefront.
Inventory Control – Good shopping cart software will keep track of your inventory and generate reports automatically.

Shipping – Nearly all shopping carts offers a shipping tool that calculates shipping costs for customers based on parameters that you set, some can even link up to common shipping methods like FedEx or UPS.

Tax Calculation – Most shopping cart software can calculate taxes, a valuable tool, especially since many states are considering requiring merchants to collect taxes for online sales.

Customer Management – Most shopping cart software has features that will let customers view their previous purchases. The program will also recognize the customer when they come back for a return visit.

Marketing – Some web store owners are familiar with selling their products directly to a customer, but have no experience in taking advantage of today’s powerful internet marketing techniques. Most shopping cart software offers integrated information on affiliate programs, social network marketing methods, and help with merchandising. Many are able to create coupons, gift certificates or other incentives as well. In addition, they provide sales reports and 'hit' or page-view traffic information as well to help optimize the customer conversion experience.

Security – Customers won’t purchase online if they feel the website cannot protect their personal information. Most shopping cart software will offer protection by encrypting information, processing credit cards through reputable processing services and by allowing customers to move through their program without having to download cookies.