Shirt prices?

I've thought about buying about 50 shirts or so with one of my websites on them to giveaway in order to promote it as it's aimed at a young audience who would wear such shirts but am unsure of what would be a good price to pay. If you've bought about that many shirts before, what's a good price for 50 standard sized 100% cotton black shirts with 1 ink on the front? I've quoted on many sites but the gap I've noticed has left me skeptical.