Tracking Running Costs

[1781cc]

I wondered what the rest of you all use to track your running costs? I currently use Road Trip HD on the iPad and find it quite useful in working out exact mileage to costs, I started with a new vehicle entry for the S8 and so far no other expenses other than fuel have been entered (Major Service is on Wednesday), new front tyres to follow along with a hunter 4 wheel alignment

Interesting to see the difference between actual fuel consumption and what the onboard computer says when it lies to you

What's everyone else's typical running costs like on the D3 S8?