Individualitee
Although I cannot honestly say that this is my new favorite design tee outlet or anything, Individualitee has one of the most professional interfaces I have seen. You can choose from a list of twelve countries and receive full localisation of both product descriptions and sizes. The designs are set in multiple colours, sizes and shapes, and are printed on Hanes or AA, which are two top quality brands. There is a very good and sturdy description of the product and print so there should be no surprises.
There are a couple of nice designs out there, too. I like the classic cassette-cross bone piece, and this cloud design has a rockin’ colour scheme.
Tees start at about £15 and extend to around £21. Shipping seems to be fairly inexpensive, and the quality should be sharp.