Look locally first, to clubs and other reefers, then look here on the selling/trading forums, and last I would look at retailers. Its the difference between a yuma you have seen in someone's tank personally for $5-$10 (or a frag), a yuma you've seen in a picture online for $20, or a description and outdated photo of a similar piece for $40. I just bought "4" yumas from a member here and ended up with 9 when all pieces were accounted for, all for $100.
Just my experience.
Marty