Could someone explain to me a lil about shopping carts, or actually a link to some info would also be great.

My biggest question is how are credit cards processed, I assume I pay a company to do that and it all ties-in to the shopping cart I use. Is it expensive, what factors decide expense. (we will not use paypal) thanks for any help

I hope these links will be helpful for you:

http://www.online-store.co.uk/shopping_cart_faq.html
http://www.utlm.org/faqs/faqshopcart.htm