We've had tanks installed at our yard for the past two years & serviced by Corrigan Oil. The tanks are provided free from your wholesale provider. You do get wholesale rates, but not as low as the service stations that are buying thousands of gallons at a time. The price is volatile with daily changes, so its hard to get a perfect comparison, but it does seem to run a few pennies less per gallon than retail price at the pump -- probably no more than 5c per gallon savings. The real savings is in crew time -- we can have one guy filling up while the other is grabbing tools & work orders. Plus, no more 20 minute "fill up" breaks at the service station. The downside is increased opportunity for theft -- you would be smart to put a security camera on your pumps to make sure no one is topping off their car for free.