The best idea I've used is a small charge but paid by an honesty box. The most annoying are the turnstiles that require exact coins only. Mostly to pay for the

The best idea I've used is a small charge but paid by an honesty box. The most annoying are the turnstiles that require exact coins only. Mostly to pay for the attendant who can't give change or accept an overpayment. If you don't have two 20p pieces your money is no good.