It depends on the size of the company buying the gas. If it's a small station, like a couple I help with their books and the four that family members own, they pay about a nickle more per gallon for gas than they sell it for. It's more expensive than, for example, Exxon, sells it to consumers for, because they pay more per gallon because of the smaller quantities and pay delivery fees. Why do they do it? If they didn't have gas, people probably wouldn't stop by to buy cigarettes, drinks, ice cream, candy, etc.. It's really a tough business if you're not associated with an oil company.
Philadelphia_GunMan, from what I've seen, buying the quantities of gas you're talking about, it would cost you [i]more[/i] than simply going to a gas station. Also, gas doesn't store long-term that well. If you're serious, buying a diesel truck/car and diesel generator would be a much better investment.z