It's kinda silly to look at it that way, Cafepress products are actually really good. I ordered two shirts and a mousepad, just one-time prints to test out how things look. I was impressed, both shirts (1 tshirt, 1 golf) have lasted well through many washes and still look great. Their stickers would probably be fine too.

No overhead, no worries, just design it and go. If nobody buys anything, there's nothing lost. If people buy like crazy, there's a few extra bucks to be made.