This sounds like a cool project!
Screen printing is all about profit.
I'm only 18 and I own my own shop fresh out of high school.
Pretty much START OUT with a cheaper press, don't go for the fancy M&R presses and such unless you have the money to spend for it.
For instance i started out on a old 6c 4s Atlas press i found in the paper shop. From there I started printing bands touring merch and built up my clients; withing a few months i had the money for top of the line equipment!
Price wise, always make your clients seem like there getting the BEST deal!
I get my shirts from Alpha there prices aren't too bad. If not not a known printer start your rates out rather cheap at first, mark them up gradually; but not so drastically that people will notice.
For supplies (ink, squeegees, adhesives etc); I used to print for an awesome screen printing supplies distributer called Pocono Mtn Screen Supply. I haven't really shopped around at other sites besides the first ones that come up on google, but Pocono Mtn. seemed to be the cheapest place for Triangle Ink, high tension wood/alum. screens, and everything else you need! ( www.poconoscreen.com
All of that is just my opinion though!
Let me know if you need anything else! :]
-Justin, Ghostwork Ink Printing