Having done some apparel branding for my company, my best advice would be to buy through a local dealer in your area rather than choosing from the countless internet shops.
Having tried both routes, I've had much better results with apparel going through a local business because it's nearly impossible to gauge the quality of the material/craftsmanship when buying online.
Alternatively, if you DO go the internet shop route, I'd recommend having them print/embroider on a reputable "named" apparel brand like American Apparel or something similar. They typically cost more, but the difference in quality can be pretty stark.
The first time I had a bunch of t-shirts made, I went the cheap route and while the online picture looked great, the material was so thin as to almost be see-through. Since then, I've been using American Apparel shirts (which they get wholesale), and have had far better results. Plus, you can have people go to the local AA shop and try stuff on, in order to ensure the right fit.
------------------------------
Brian Bird
Co Director
Broadway Life: Student Group Travel
http://www.Broadway.Life
info@broadway.life
(212)-321-0950
------------------------------