Dumfries Extra - Petrol Filling Station: 170.9p a litre, 2.9 miles away. 4.0p a litre cheaper: saves £2.20 a tank, and costs about £1.12 of fuel to get there and back. Worth the trip.
Heathhall Dumfries Esso Express: 171.9p a litre, 2.1 miles away. 3.0p a litre cheaper: saves £1.65 a tank, and costs about 82p of fuel to get there and back. Worth the trip.
Focus Motor Store Ltd: 172.9p a litre, 3.0 miles away. 2.0p a litre cheaper: saves £1.10 a tank, and costs about £1.17 of fuel to get there and back. Not worth the trip.
On a 55-litre tank at 40mpg. The distance is straight-line rather than by road, so a real trip is longer than the one costed here.