I just recently purchased a couple bonsai trees from Bonsai NW and I am happy with the purchase. They are more than reasonably priced and know their trees. My only complaints are the lack of hands on assistance in helping me choose my first trees and the fertilizer they recommended which is NPK 7/9/5 - When purchasing fertilizer do your research, you will find an even matched NPK such as 10/10/10 or 20/20/20 to be more beneficial for bonsai trees.
Pros: Inexpensive, Lots to choose from
Cons: Lacking service