BRANDS OF HEAVY COTTON TEES? "THICK" TEES?

I am trying to go to a local decal store and get some tees custom printed for my own use. i don't usually wear t-shirts, but i have some from abercrombie that are really "thick" and heavy. I am looking for one of the regular "blank" shirts to use. I can't seem to come across any, and moreover don't know where to really look. thanks in advance!