Yeah, I mean, from a pure money standpoint, even if you only get 10 gallons of fuel; That's 40¢ off each gallon for those ten gallons ($4.00). If you were to just deposit using a money order (71¢) You save $3.29 for doing basically nothing more than you already were. ($13.29 if you get all 35 gallons).

Free money is free money. Its even better when its just free and you barely have to do anything to get it.