I used 4 Imprint. It was free if you are buying some of their product. I ordered 20 shirts. I had an idea for what I wanted, they gave me a number of options and styles. I worked back and forth with them tweaking and getting a final version. Never felt pressured to make a decision, the response was very good. In the end they also (i think i requested) sent me lots of different formats of the artwork. pdf, png, tiff, eps and any other file version I needed.