You'll probably have better luck at a store near you. In your town or city there'll probably be a T-Shirt printing business which you can go visit. That would be better than getting them done online as there's a chance the design could go wrong on the Internet, with little chance of the website refunding you, whereas in the shop you can talk to the printer and tell them exactly where you want it etc. They're also more likely to refund you if it goes wrong or something! :)
I would say try http://www.digitalmayheminc.com
I have tried other screen printing sites (I do this often for work), and so far as I know, this is the best price with great quality and the topper for me was the great customer service and communication (what I look for). They will use your designs or help you come up with one. They have a pretty nice catalog on their website with a lot of options on plain shirts to choose from. (From stylish womens tee's to heavy duty hanes.)
They are pretty cheap, obviously the more you order the cheaper it is. Very comparable to anything else I've seen and better quality.