www.artapart.com
They are cheap and use high quality shirts that won't fall apart. However, if you have a bunch of colors going together in great detail, it might not be the best place since they aren't always precise. We used them to make our fundraiser shirts which had a big copy of our logo (the monkey face) on the front and some text on the back. They turned out nice and it was just $7 a shirt if I remember correctly.