Vaughan currently supplies all of the Craftsman hammers with the exception of the dead blow hammers, made by Nupla, and the imported flex claw hammer. The hickory handle ball-peen hammers are a great deal.
Flea market may only be good if they started good, rounded hammer faces are great for skipping off the heads on nails and smacking fingers, cheap handles sliding as you hammer and the prying end snapping on one side or the other are all issues I've seen working with people who have cheap or flea market specials. Only time I even tap a finger is using someone's cheap hammer, I've put up plenty of siding and shingles without an ouch with my estwings.The Craftsman black hammers work just fine. They are Estwing produced I believe so same hammer different handle shape and colors may vary.
With that said, the Snap On ones aren't that expensive either.
With that said, flea market hammers work the exact same but might need a new handle after a while.
Choose your poison.