Captain raises some good points - I initially read the OP as being contacted by the dance to shoot the event. Certainly if you're not the prime photog. then the rates would be adjusted accordingly. And if the experience is worth more to you than the $, then you may have a case for some concession in that regard. But do be aware that once you establish your "value" (perceived by what people pay...) as low, it's much more difficult to raise it later on.
(Don't ask me how I know this
)