I have been getting mine from True Value Hardware at $8.59 per gallon. If you buy from Sherwin Williams ask them to start you a "business account" and it should save you $2 per gallon or so. At our Sherwin Williams it is $10.69 so the even with discount it is no cheaper than True Value for me. Sherwin Williams can also order it in 5 gallon containers. I have tried Lowes and Home Depot and still can't beat True Values price.
Has anyone tried E85, its found a local gas stations around here for less than $2 a gallon. I realize it contains 15% fuel, but 85% ethanol ain't all bad.