I find this sort of fascinating. It's a list leaked from a booking agency showing the asking prices of a huge list of popular musical acts, from Madonna ($1M+) down to Westland (who?) ($1k+).
(h/t
Marginal Revolution)
ETA: Original source
here, with an update that because this is from a source which does third-party booking, prices are likely to be inflated. (I still think the Indigo Girls aren't asking enough.) Also, that site has informative commentary.