The cheapest petrol near you is not always the cheapest option once the trip is included. Begin with the size of the price gap and the amount you plan to buy. If the difference is 2p per litre and you buy 30 litres, the maximum pump saving is 60p.
Count the extra journey
Ask whether the station is already on a route you need to take. If not, estimate the round-trip distance and the fuel your car will use. A detour also has a time cost, even if you do not assign it a cash value. Do not rely on a straight-line map distance as a road-mile estimate.
CarFuel's local price results can help you identify candidates, and the journey-cost calculator can make the comparison more concrete. Use the same grade and check the record date on each result.
A useful rule is to set a maximum detour before searching. If a station falls outside that limit, ignore it unless it is on your way for another reason. Verify the pump price before filling, because a listed record is not a guarantee that the price has not changed.
Prices and availability can change. Check the current pump price and the fuel grade approved for your vehicle before filling.