Cloud Bunny,
By actually showing up, you are declaring your willingness to part with money. Obviously many suitable candidates don't show up as they are unwilling/unable to pay.
By the very fact that only those willing to pay show up, self selection has already taken place. To suggest that anything other willingness to pay is the prime selection factor is thus nonsense. A selection is being made the moment you make the application. Thereafter, all other selection decisions are made on the basis that you will be prepared to cough up.