2 female + 1 male = LOTS of babies so be prepared.
I paid $1.49 each for my male green snakeskins and for my male mosaics. Females are usually a bit less. BUT like everyone said, it depends upon the variety and the size of the tail.
Well bred guppies from private breeders can go for $45 a trio (some even MORE !)
So it really does depend upon the type.