About shopping cart designing?

creating your own shopping cart is not a simple 1-2-3.

There is allot of things to take into account when rolling your own cart.

the biggest thing for designing a shopping cart is security. This IMHO is the MOST important element of a shopping cart. No shopping cart has 'the' perfect security model, but if done right you have have a very nice secure shopping experience for your customers.

there are other things as well, like session management, layout, flow of the cart, payment flow, what database base format to use (MySql is the most used if i am correct), encryption of sensitive customer information like CC Cards (if you are going to store them).

and that is just scratching the surface.

before you start though, you have to decide on the language you will use to create it.

the top two languages for this in my opinion are: PHP and ASP.NET. but can be done just the same in others like perl, ect ...

once you decide on the language to use, look at some examples of cart created in it. if you go php, a good free shopping cart is osCommerce. FOr ASP.NET search through codeplex.com or codeproject.com for some examples. There is also SourceForge.net as well.

You could try using an open source shopping cart like zen cart or oscommerce. But coding a shopping cart from scratch sounds like a hard task.