dup

purchased a voucher from one of the group-buying sites...  two sets of cheeseburger, fries and milkshake, 55% off...

me:  'i really liked their milkshake...  if they still have a voucher, i'll buy again...'

friend:  'i still have one...  i printed two...'

me:  'huh?!'

friend:  'ooops...  yeah...  it's just a duplicate...  they have the same code...  we'll have to buy again...'

of course!  \m/