We often quote rail fares in pence per mile, but I have not seen this comparison for buses.
Stagecoach in Cambridge. From Cambridge Station to Campkin Road in Arbury. About 3.1 miles by the shortest distance (if walking or driving) or about 4.5 miles by the bus's route. Cost ^3.20. That's either ^1.03 or 71p per mile, depending which distance you choose to use.
Plusbus costs ^3.20 (or ^2.10 with railcard) and offers an unlimited use of buses within the city for one day. A taxi for the same journey normally costs about ^9.
Excluding fixed price areas, such as London, I wonder if anyone can beat this fare for lack of value for money?
You may well have a point on this one variable however I think there's more to "value for money" than just the headline cost per mile - reliability, levels of overcrowding, comfort, time the journey takes, accessibility, frequency of service, standard of customer service/experience etc etc?