I started with one design and after it sold, I reprinted and added another design. And another and so on.
CHL is right though. Customers like *choice*. So even though they liked the one design, I got emails all the time asking if I had more designs. Some people won't buy if they feel like their choices are too limited, but you can still get sales if your one design in compelling enough.
I think once you have 3-5 designs, people are more comfortable with their choices, although even if you have 20 designs, you still may get the occassional "wish you had more choices" email
