What brand of performance chip is best for increasing gas mileage?

I want to know where I can find a chip that really increases gas mileage for my 96 Ford Bronco 5 liter. I'm 16 so gas is pretty hard on my wallet. I've found some online that are supposed to increase gas mileage by 8 MPG for $50, but I don't know if that's true. So could someone tell me the best chip for increasing the mileage? Thanks and please no b.s. answers.|||your vehicle doesn't use a chip, you have to buy a re-programmer and reprogram the computer, that will run you 3 or 4 hundred dollars and it won't increase your gas mileage whatsoever, it will just give you better performance.|||cars usually come from the factory with optimal fuel performance..aftermarket chips usually sacrifice fuel mileage for performance