It’s easy to design and sell your own T-shirts. Especially if you let somebody else make them!
I made the Quake Chaser shirt on Cafe Press.
Here’s another design I put together using a a bit of tweaked clipart and some text from Zazzle’s online designer. Altogether it took about 3 minutes.
Get started designing stuff on Zazzle…
There are loads of other sites that offer similar tools/products. The shirts may not be the cheapest available- but for one-off custom art it’s a pretty good deal. It’s fun and easy!