zipcar.com has a free $40 Credit for New or Existing Members when you apply coupon codes holiday1, holiday2, holiday3, holiday4. If you are not yet a member if Zipcar they will charge you $25 to make a new account so this free credit is best for existing members, but if you want to make a new account you can get the credit as well. Zipcar is a car rental service that allows you rent cars by the hour