I don't know what you're paying for Petrol..... but in England we're paying up about £1.30 - £1.45 per litre. Here are some tricks to get your money's worth for every Litre from an expert in Australia:
"Here at the Shell Pipeline where I work in Melbourne, we deliver about 4 million litres in a 24-hour period thru the pipeline.. One day is diesel the next day is jet fuel, and Petrol, regular and premium grades. We have 34-storage tanks here with a total capacity of 16,800,000 Litres.
Only buy or fill up your car or truck in the early morning when the ground temperature is still cold. Remember that all service stations have their storage tanks buried below ground. The colder the ground the more dense the Petrol, when it gets warmer Petrol expands, so buying in the afternoon or in the evening....your litre is not exactly a litre. In the petroleum business, the specific gravity and the temperature of the Petrol, diesel and jet fuel, ethanol and other petroleum products plays an important role.
A 1-degree rise in temperature is a big deal for this business. But the service stations do not have temperature compensation at the pumps.
When you're filling up do not squeeze the trigger of the nozzle to a fast mode If you look you will see that the trigger has three (3) stages: low, middle, and high. You should be pumping on low mode, thereby minimising the vapours that are created while you are pumping.
All hoses at the pump have a vapour return. If you are pumping on the fast rate, some of the liquid that goes to your tank becomes vapour. Those vapours are being sucked up and back into the underground storage tank so you're getting less worth for your money.
One of the most important tips is to fill up when your Petrol tank is HALF FULL. The reason for this is the more Petrol you have in your tank the less air Occupying its empty space. Petrololine evaporates faster than you can imagine. Petrol storage tanks have an internal floating roof. This roof serves as zero clearance between the Petrol and the atmosphere, so it minimises the evaporation. Unlike service stations, here where I work, every truck that we load is temperature compensated so that every litre is actually the exact amount.
Another reminder, if there is a Petrol truck pumping into the storage tanks when you stop to buy Petrol, DO NOT fill up; most likely the Petrol is being stirred up as the Petrol is being delivered, and you might pick up some of the dirt that normally settles on the bottom."