If you are looking for a new self fulfillment shopping cart for your customers...Then you have to check this out...
www.redcart.com
Best customer service EVER! Every time that I emailed them I had a response within 15 minutes, even if it was 2am!
The feature that I love most is that there is a "store" where you can sell products and services. I made it so customers can create their own wedding packages!
I set a general package that they can "add-on" albums, second shooters, parent books, guestbooks etc!
The admin side of it is fantastic! You can view your profit margins, averages and more! In the print prices section you can add what it costs and redcart adds the markup for you! (of course you can change it to whatever you want)
I am still working on mine, but you can get an idea here: www.jamieleephotographyclients.com/clients
they have more demos at www.redcart.com
BTW: I bought it yesterday afternoon and it was online and ready an hour later. (Tommy set it up for me)