So, the shopping cart I am using is just not working for me. So, I'm looking for one with a few specifications. Maybe someone has a recommendation?

I need to customize my coupon and shipping options I sell two different categories of items...On one category I would like to offer 35% off when spending 100 dollars or more but only in that category. I don't want to offer that coupon towards other items in a different category. This feature I have found in many of the carts I looked at. It's the shipping/delivery I am having trouble with. I would like to offer free delivery in a certain area, maybe by using a zip code.

I am not one for coding and would just like a simple program. I have downloaded demos where I don't even know how to instal the program...take OSCommerce for example. I can't even try it because I don't know how to install it.

These seem like simple enough specifications but I cannot find the right cart.
Oh, I'd also like to keep it under $500

Thanks in advance!