Someone asked why keep the dog to the age it is before selling it?, might be the guy was deliberating which to keep, might be deep down he didn't want to part with either.
IMO, if you can walk out with that dog, it's in good nick, vaccinated, wormed, chases catches and carries back jumping fences along the way and has good recall, broken to stock, all of which the guy selling assures us it is, then that's a cheap dog.