dab you are correct with your math
I should have clarified myself with my above statement. Last time I was at my local Fleet Farm they had the 16 oz cans and the 1 gal. can (both every day price) and after doing the math (on my cell phone in the middle of the store) there was not much savings, like I said about half a can.
It's pretty rare that I see it on sale much around my neck of the woods (just north of the twin cites). I believe the going price is usally around $7.00 for the 16 oz can. I was just at NAPA on Saturday picking up parts for my trailer, I should have looked but did not.
Watch for the sales this Friday, I believe in the past I have seen it go on sale.