Rontec Cardiff West, CF72 8SA. A motorway service area, where you have no choice.
What it is charging
Unleaded: 177.9p a litre, 6.2p over the national average, filed Tuesday 27 October
Diesel: 205.9p a litre, 7.2p over the national average, filed Tuesday 20 October
Super unleaded: 197.9p a litre, filed Tuesday 27 October
Super diesel: 225.9p a litre, filed Tuesday 20 October
Unleaded within 5 miles
Asda Cardiff Coryton Supercentre: 168.7p a litre, 2.9 miles away. 9.2p a litre cheaper: saves £5.06 a tank, and costs about £1.11 of fuel to get there and back. Worth the trip.
Sainsburys Talbot Green: 168.9p a litre, 3.8 miles away. 9.0p a litre cheaper: saves £4.95 a tank, and costs about £1.45 of fuel to get there and back. Worth the trip.
Mfg Treforest: 168.9p a litre, 4.6 miles away. 9.0p a litre cheaper: saves £4.95 a tank, and costs about £1.76 of fuel to get there and back. Worth the trip.
Mfg Morrisons Cardiff Tyglass: 168.9p a litre, 4.7 miles away. 9.0p a litre cheaper: saves £4.95 a tank, and costs about £1.80 of fuel to get there and back. Worth the trip.
Asda Leckwith Road Superstore: 169.7p a litre, 5.0 miles away. 8.2p a litre cheaper: saves £4.51 a tank, and costs about £1.92 of fuel to get there and back. Worth the trip.
Cardiff Tyn-y-parc Express: 169.9p a litre, 4.0 miles away. 8.0p a litre cheaper: saves £4.40 a tank, and costs about £1.54 of fuel to get there and back. 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.