There are various eCommerce architectures available; perhaps a starting point would be to determine which approach best addresses the projects needs. Option 1 could be to utilize a turnkey eCommerce solution such as “OsCommerce” or “Zen Cart”. Option two could be a custom build application; this may be a costly proposition for some, however the advantages of complete control of the cart and functionality may be justifiable. The third option, and perhaps the most common, would be the modification of a turnkey eCommerce solution to address the needs of your organization.
Once you have identified which approach is aligned with the business needs of the company, it will make the process of evaluating eCommerce architectures that much easier.