Google Maps includes information about toll roads (roads where you have to pay a fee), at least for the US. Chris Maloy, who sent me the tip, says:
"This has been long been missing from Google, but available on most other map services. I like seeing this on the detail, however it would be nice to have on as an indicator on the map, or where the toll booth is (helpful for long toll roads), and finally the cost of the toll."