Mr. Ray Coyne:

Yes. It could be any token. Someone would get on the bus and make his or her journeys through the day or week, and the system will dynamically update. If a person makes just one journey and the fare is €1, it will charge €1. If that person did 20 journeys at €2 apiece or whatever, it will charge him or her after the event. It will also charge the cheapest fare.