registration form and assorted fees

Does anyone know of a way to use ‘pay as you go’ as a fee on a form that has specific fee amounts for other activities? Our event has free activities, fixed price activities, and some where the fee will be paid by an individual at the restaurant. If we use $0 in the fee amount, then it translates as FREE, even though in the description we are clear about the cost. And the fee columns can only be hidden when all the fees are free.

Is there a workaround anyone has found? Thanks for your help in advance!