I'm thinking of setting up an online store with digital products. Any recommendations for the cart? I like osCommerce, but I'm not sure that it is responsive. I'd like a responsive cart that allows digital downloads, is inexpensive, and easy to use. (If one exists with all those things. lol)

I prefer OpenCart it lets me have all I need and then some. Can do it all and then some.

I have been using CC Shopping cart for a while and have been using it to build all my stores (currently have 7 stores up and running). Unfortunately I had to search for another product because CC has nothing to fulfill my clients needs at this time. I know it wont be long once they get the other responsive apps done but in the mean time I have been testing out some other software.

I have been testing out Prestashop and so far I really like it and it supports digital downloads, coupon codes, advanced shipping features, and thousands of additional modules that can make your store very dynamic. I have a client site that I have started building if you would like to have a look just private message my your email address and I will share the link with you. The real magic happens in the administrative panel "Store Backend".

Its very similar to WordPress but much different. There is a lot more focus to eCommerce. Oh and it is also responsive.