POW 9

Tony goes into Dave's Army-Navy store and buys a hat for $14. He gives Dave a $20 bill. Dave doesn't have any change, so he takes the $20 bill across the street to Laura, the clerk in Watson's Hardware store. Laura trades Dave's $20 bill for twenty $1 bills. Dave comes back and gives Tony $6 in change. Tony takes the hat and the $6 change and leaves town forever. Half an hour later Laura comes over to Dave’s store, just furious. She has discovered that the $20 bill he gave her is counterfeit. Dave, of course, makes it good, giving Laura a genuine $20 bill he has in the till from an earlier sale. Question: Now that it is all over, who came out behind? And by how much?