Watch out -- there is currently a flood of fake Yves Saint Laurent Muse bags up for auction.  They are typically black or white and -- here's the tricky part -- offered with cards of authenticity.  A few of them are real, but look closely -- the numbers on the cards pictured on the knock offs are typically the same.  Also, if the the zippers on authentic YSL bags say anything, they say "YSL", nothing else. Unfortunately, if the price seems too good to be true, it probably is.