I baught most of my mbuna for $1.50. I guess that's how I started out with them, no need for deep pockets there haha.
Great finds that I've passed up have been $2 P. electra and a $2 Nanochromis transvestitus. Thinking back now I REALLY should have baught that Nanochromis but didn't cause I like to buy pairs...
I also scored on a bunch of baby Albino Eureka red peacocks, P. demasoni, and O. tetrastigma when a breeder was having a moving sale. No individual fish cost me more than $2.
My greatest find has to be S. jurupari though. Out of nowhere my boyfriend and I get the urge for some jurupari, know we're NEVER gonna find any around here and after visiting the one shop with the most random things we happen across a tank of baby Satanoperca mislabelled as "Clown Ruby Cichlids". It was so crazy, we took all of them.