I use Instaproofs, and have been very happy with it thus far. Free, no set up fees or anything. Instaproofs does take %15 of the product cost, but to be honest, it isn't much if you consider the fact that the service is free, they deal with all of the credit cards and payments, as well as refunds, and the process is very simple. You get paid every two weeks and the money can be deposited right into your bank account, Paypal account, or via check in the mail. It's not a print lab, it is just a storefront, you will have to fulfill the orders yourself. They do offer a print lab that fulfills your orders for an extra fee, but I don't personally find it worth it. Better to create the prints yourself or use a print lab of your choice!