If you want to screen print, you can buy a set up for a few thousand bucks. The cheaper route is to buy a heat press. You can get a business started with a heat press, and inkjet transfers for under 1000 dollars. You might even be able to do it for around $500, but $300 is pushing it. You can get a small heat press for around $400 new (i think) not the top of the line or anything, but it'l get the job done. Transfers will cost .40 to .75 each. For you probably .75 since you wont want to buy alot to start out with. The website for them is
http://personalizedsupplies.com . They sell good quality paper cheap. The final thing you will need is a good inkjet printer. Epson is highly reccomended, with the magic inks at tlm supplies. Good Luck.