I played a game this evening at the ANU Chess Club that was essentially decided by a pretty cheap trap. But having looked at it afterwards, even if White avoids the worst of it, Black still has enough for the pawn.
1.e4 e5 2.Nc3 Nf6 3.d3?! c6!? (This is the start of the trap) 4.Nf3 d5 5.exd5 cxd5 6.Nxe5? d4 (This is the idea behind 3. .. c6). In the game White went wrong straight away with 7.Ne2?? Qa5+ 8.Bd2 Qxe5 -+, but even after the best reply 7.Qe2 Be7 Black is still slightly better.
So while the win of the piece might be 'cheap', the line itself may have some merit. The only issue is that the position after White's third move would be so rare, that you might go some time before you get a chance to play it.