Checkout http://www.kommonthread.com/ They're working on a new program to help promote startups using T-shirts

I cannot recommend http://progressofdesign.com/ enough. I've ordered from them 3 times and couldn't be happier. Cheaper prices than most other places I've used in the past and great quality. I wanted to print a larger than average design and they accommodated me for only a small bump in price when other companies said they couldn't even do it.

I bookmarked Threadbird - http://www.threadbird.com/ recently, from the folks of Storenvy I think, but your pricing is much more competitive! Threadbird got a bit more printing options and materials.

I've wanted to rekindle "Startup Schwag" as I didn't get to get on it for very long prior to its close down.

we use vistaprint, primarily because the UI makes it easier to design shirts. You should test out the quality of shirts on a short run first.

If you keep an item in your cart, they will send you a coupon. If you buy a small amount, they will send you a coupon that you can use on a bigger order.

I've used Queensboro.com. Tons of options, and solid pricing. Would definitely use them again.