Quote Originally Posted by VehiX
Isn't regular cheaper not only because it's less octane but because it tends to be the bottom of the barrel or mixes of different grades?
I got bad news for ya. Midgrade is just a mix of the low octane and high octane fuel.

Almost all gas stations have just two tanks in the ground, low and high octane. They mix them at the pump to get the in-betweens. In many cases, you can actually mix it yourself (pump 2/3rd low octane and 1/3rd high octane or whatever ratio it takes) and it is cheaper than letting the station mix it.

However, you are not alone in your misconception, the gas companies actively seek to mislead people into thinking just that, to trick you into giving them more money.