If I have to go and pay for my own clothes I just go to Value Village and find some. They just had a 50% off sale on Monday.
I like plain ones cause they dont have stupid written stuff all over them.
The only shirt I can remember having with stuff written all over it was one with a picture of Billy Ray Cyrus and a heart on it with "Achy Breaky Heart" written on it. I got this shirt when the song was popular though.
Woot launched a t-shirt site a while back. Woot Shirt : One Shirt, No Shoes, No Service (SM)
They have themed derbys where designers submit their work and the community votes to choose what designs will be printed. Not every one is great but I have some some interesting stuff there.