Has anyone here ever written there own e-commerce system? I've looked at a lot of them and I can't find any that fit my needs. I just need something pretty basic but I do have some specific needs so I think I'm going to write one. I don't have much experience in that area though so I thought I'd see if there are any potential trouble spots I should watch out for.

I think I will be using authorize.net for the gateway. They seem to have pretty good docs and make it seem like a pretty straight forward deal.

I did, a few years ago. As I recall, it was mostly straightforward: the toughest part was devising a flexible system for storing product options. Bear in mind that what I wrote was intended to be suitable for a wide variety of applications, it meant coming up with a fairly involved system for storing all the possible combinations of product (e.g. for clothes it might size, colour, fit; for a computer component it might be speed, compatibility etc) and the pricing implications for each combination. Of course if you're writing this for a specific project then that might not be such an issue.

Have you checked out Magento? I've only just started working with it but it seems like a very well thought-out system and might have the functionality you need.

I've made a couple, but with Paypal for payment.

The tricky bit on mine is this: Selling garments where, not all styles come in the same colors, all colors don't come in the same sizes, and there's an up charge for certain sizes.

If you can handle db's and your choice of language, it's not that hard. To me it's easier to right my own than deal with an off the self version.

I did look at Magento, it looks really nice, unfortunately some of the features I would need are only available in the enterprise addition. I don't think I can justify the 11k price tag for that. Luckily what I need is very basic as far as the products go, it's basically only one type of product really. The thing that would force me into the enterprise system and screws me on most pre built systems is that I need the ability for multiple store fronts and the ability to define different administrator roles/permissions spanning multiple stores. So I basically I just need simple product features and options but detailed control over administrative roles. Everything I look at seems to lean the opposite direction.

Lucky for me I think that is the easier of the two to handle on my own.

So thanks for the info. I think never having worked with ecommerce and the fact that it deals with money I was afraid I may have been missing something and I just needed some reassurance that it wasn't anything out of the ordinary.

for payment processing, have usedhttp://www.dotnetcharge.com/. There's ways around their licensing if you need to do more than one - just need to be creative

And writing an e-commerce solution is generally pretty easy. It depends on what all needs to be implemented. In my experience, the trickier part gets to be any sort of inventory control for product combinations - such as large shirt in red, large shirt in blue, etc.