My first time into Bowerstone Market I stumbled onto Mystical Mungo's (yeah, the same guy you bought the Music Box from). He told me his store/stand wasn't quite up and running yet, but he GAVE me a bunch of different things (including a Helmet which I didn't yet have) one of which was the Dog Flip Trick Book. Cost: 0 gold!)
Note: Mystical Mungo's is on the Lower Level North, right down by the river.