I tried to buy 1000 gallons of diesel for a small fleet of trucks to lock in the price, I was told to get a break (which amounted to a penny or two per gallon) that I would have to commit to 10,000 gallons! YIKES.
Many of the customers of my company are gas station operators, the new trend in the industry is to set goals at gas stations so that they work on a 0.00% profit margin on fuel. The operations that are close to that make their money on merchandise & foodservice sales inside the gas station, car washes, etc. Translate that to the typical consumer (me) and the profit margin (before labor, taxes, etc) on retail fuel is only a few pennies per gallon. Therefore, buying & storing fuel at home in 100 gallon tanks is a CONVENIENCE that will probably cost you a few pennies a gallon more for the fuel than if you bought it at the pump. . . especially if you factor in the cost of your tank and pump set up.