A lot of people have the misconception that waiting longer to fill up your tank automatically saves you money. The fact is, you haven't burned any less fuel, and are going to need just as much to fill up your tank as if you had filled it in more frequent intervals (assuming you only stop at gas stations that are along the way to your destination). The only method that works for saving your money, is to time it for when the gas prices are lowest. This is probably one of the methods mentioned in
>>5. I only say this because of the point
>>5 was trying to make, however that comment was actually irrelevant to the OP. The goal here from what I read isn't to save your own money, but to hurt oil companies by simply not spending any of it on gas.
I mentioned in
>>3, and
>>4 also raised some points as to why that won't work as well as that image above suggests.