The IRS publishes a standardized mileage rate. This isn't a very accurate description of just the simple dollar costs of commuting by car, but it's at least a number that actually means something. Multiplied by your commute multiplied by times that commute is traveled gives you some idea of the costs of the commute.

That it presents somewhere in the order of a 100 USD to 300 USD in monthly additional costs for a ten mile difference in travel time to you work is almost certainly an underestimate, but it's really easy to forget these sort of tradeoffs when looking at a home to buy or rent or comparing different job offers.

The math for public transportation is a lot harder, and generalizes less (one person's relaxing train ride is another person's battle with nausea and agoraphobia). It's still a useful place to start.