To date this year I've spent €930 on petrol, so I decided to work out exactly what a trip home in the car costs me in terms of fuel and tolls. The distance from my gaff in Cork to my home is 340 Km, give or take a few metres.
I filled the car at my nearest petrol station before leaving and filled it again at the nearest station to my home, which was charging 131.9 c/L at the time. Filling up after the journey cost €32.96. During the trip I went through three toll booths, totalling €5.60. Therefore I can guesstimate that the round trip is approx €77.
That's a fair bit - and €13 more than a return trip on the train. Incidentally I spent €800 on petrol in the same period last year.