I've written before about the hidden costs of driving; maintenance, depreciation and insurance. The IRS allowable deduction is a good catch-all number for estimating the cost of travel. It currently stands at $.505 per mile.
This makes it easy to estimate the cost of a round trip; the number of miles one way is about the number of dollars it will cost you. I found this very sobering when I began to consider the places I normally travel.
Each week, I meet with a writing group in a local library. The library is 4.54 miles away, so each meeting costs me $4.59, or around $250 per year. I hope that my writing improves each year by at least this much!
My good friends Brian and Carolyn live on the other side of Columbus, 21.42 miles away. Our Friday night get-togethers costs whichever drives to the other's house $21.63, before we even depart for a restaurant.
My in-laws live in Dayton, 74.68 miles away. A quick trip back and forth costs my wife and I $75.