[Isaac Zackary]

So I have a loyalty card with a local supermarket that also offers discounts on fuel. When I buy $100 in groceries I get 10¢ off per gallon. Every time I buy $100 I get another 10¢ off, which can add up for each month. So if I buy $400 of groceries I can get 40¢ off fuel that month.

But there's a catch. You can only use it once that month. So say I buy $100 one week. I get 10¢ off that week. If I buy fuel the discount is used. So then I have to buy another $100 to get another 10¢ off. But what if I hold back buying fuel every two weeks. Then I get 10¢ the first week for buying $100 and then add 10¢ more for another $100 for a total of 20¢ off per gallon.

As you can see, the longer I wait the more I get off per gallon, at least up to a month (it resets every month.) So if I could fuel only once per month I could get a full 40¢ off. (Actually only 30¢ because we only spend about $320 per month in groceries.)

So how do I do that? I drive at least 280 miles each week at around 55mpg. That's a over 20 gallons of diesel per month. The problem is I only have a 15 (or is it 13) gallon tank on my car. So what I do is I got two portable yellow 5 gallon diesel cans for cheap at a yard sale. Now I go once per month and fill up the car and the diesel cans too. Then, as I run out of fuel I put the diesel from the cans into the car's tank. Then do the same next month. That way I get the biggest fuel discount possible from the local supermarket since I only buy fuel once per month.

20 or more gallons multiplied by 30¢ is $6 or more that I'm saving per month. It's like getting two free gallons.

I do see one problem though. Storing fuel in a couple of cans, even though they're rated for fuel, may be a hazard and may not set well with the landlord if she finds out. But so far it's been working well.