I've done t-shirts in the past although just one color. I recently built a 4-color press, and make the art and screens myself. If you look around on the net there are lots of sites describing the process.
I use water based ink instead of plastisol because the plastisol needs a flash dryer to cure. I order the shirts wholesale and get them for around $1.77 ea for good 6.1 oz cotton shirts.
All in all it's not a mysterious process if you are somewhat handy. I just ran my second batch of 50 shirts yesterday, took about an hour.
The first batch I basically gave away, they're great to get girls dancing, "first people dancing get a shirt". Kind of goofy for a cover band to have t-shirts but it sets us apart from the other cover bands that don't have them - lol
I'll probably sell them for $5.
The nice thing about doing them yourself is that you don't need to order tons to get the volume pricing.
You should be able to do you logo in just black without a fancy press and have it look pretty cool. If you wanted, run different color shirts.
You'd just need to build a platen to hold the shirt and hinge the screen at the back to hold it. That's how I did my first shirts for years.
Oh, here's plans for an easy one-color press;
http://www.screen-printing-t-shirts....ess-plans.html