One copy, fifty copies or more, it is always cheaper at Kinkos or Staples.
FYI - Years ago staples had self serve copies where you make your own copies and went up to pay at the cash on the honor system. Now that you have to buy a prepaid card to get copies, there are no longer any crowds at the self serve. When it was self serve on the honor system most people made 50 copies and paid for 10.