Yeah, hatchery "ameraucana" are really easter eggers since they are not bred to the establish standards. They are still nice birds, pretty when grown, and are good layers. $15 isn't bad for a pullet. Not sure what they normally go for in your area. Around where I live they usually sell for $12 or so a piece.
Likely the guy you got her from didn't know any better. Hopefully she lays pretty blue/green eggs for you when she starts laying.