The rules regarding how and when fares are to be paid and for how long they remain valid are many and varied. Rail and bus systems usually require the payment of fares on or before boarding. In the case of taxis and other vehicles for hire, payment is normally made at the end of the ride.

Some systems allow transfers: that is to say that a single payment permits travel within a particular geographical zone or time period. Such an arrangement is helpful for people who need to transfer from one route to another in order to reach their destination. Sometimes transfers are valid in one direction only, requiring a new fare to be paid for the return trip.

In the United Kingdom certain Train Operating Companies, such as South West Trains and Southern, have Revenue Protection Inspectors who can issue penalty fares to passengers who travel without a valid ticket. This is currently a minimum of £20 or twice the single fare for the journey made. In Toronto, the local transit agency charges $500 for people evading a fare, over 181 times the cost of a regular fare.

Farebox