Type in on google: create a T-shirt online, and click either the first or second link. Then you can make a shirt and add text (you can find funny geek quotes etc. seperately on the internet) and its super cheap. Hope it helped and hope i can get a best answer x :)
Check out http://tshirtscanada.com/
Excellent prices, good work.
You only have to order 12 shirts to get favorable pricing.