auxiliary fuel tank for diesel truck

Sister in law kept good track by using gas buddy and planning where to fuel. She says they have almost it paid for after 6 years. She also mentioned the biggest savings is planning what state to fuel up in if given a choice. Such as AZ and Calif. They fill up close to state lines where next state over has higher taxes. She started keeping track because her husband said it would pay for itself shortly. He has it set up without any pump. He gravity feeds it thru a hose from extra tank in pick up bed to regular fuel tank. She hasn't figured in cost of hauling it around according to her. She has her numbers down to the decimal and reminds her husband often how quickly or more accurate, how long it has taken to break even. Or as she puts it, almost back to zero.

Personally I would like one, just because of a couple times having to fuel at places that are taking advantage of their location. Such as Death Valley CA. I think all the station owners are related to each other at that lovely place.