In Australia, some of the supermarkets gives a fuel voucher for a discount of $0.04 per litre at its affiliated service station. The two major affiliations are Coles with Shell and Safeway with Caltex. As our car has a tank capacity of 159 litres, we usually try use these vouchers as much as possible. To get the discount voucher, your grocery bill needs to be $30 or more for a single transaction. (I have seen shoppers separating their grocery purchases so that they can get more than one discount vouchers!)I have always wondered if these vouchers actually save you any money?
Last night, I was filling up my 4wd at the local petrol station. This time, we haven't filled it for a couple of weeks and the tank is running quite low. With the price of diesel at about $1.24 per litre, it would cost $197.16 to fill the tank right up.
However, with the discount vouchers, there are several conditions.
- A single transaction can only be use for 150 litres of fuel.
- The voucher has a validity period, usually 1 month.
So as I was filling up my 4wd last night, I noticed a sign at the bowser saying that if I spent $5 in -store, I get a further $0.04 per litre discount. This gives me a total discount of $0.08 per litre.
Working through the maths,
Maximum saving is 0.08 * 150 = $12.00
Purchase to get extra $0.04 discount = $5.00
Effective saving is 12.00 - 5 = $7.00
This is good news as it would be worthwhile for me to spend the extra $5 in-store to effectively gain an extra $1.00 saving.
However, if I spend more than $6.00 in-store, it would be better if I just stay at a discount rate of $0.04 per litre as my saving would start to diminished.
So I guess that next time I rush in-store and purchased a chocolate bar and a bottle of soft-drink for the extra discount, I need to be careful not to spend more than $6.00.
Around the net, I found the following resources for saving fuel on cars.
- JD at Get Rich Slowly gives his 23 top tips on better gas mileage.
- ethoskiwi has a blog at Increasing Fuel Economy telling us how to do it.
- Some Fuel Saving Tips from Pierre Ford. This is interesting as Pierre Ford is a car dealership the Ford Motor Company based in Seattle, WA.









