I use Vistaprint, I have a stamp with my name, title, and all my licence numbers that I use for student logbooks, etc. I designed it with incredibly small, but just readable text, for obvious reasons.
Simply a case of design it in a suitable tool on your PC, upload it as an image, Bob's your uncle. The prices keep going up and down like a yoyo, and if you're not in a hurry, try registering, putting it in your shopping basket, then leaving it. Usually they design special offers for you around a week later, effectively giving you a significant discount.
Also great for business cards, flyers, and anything else of the like.
G