Jesus Jones' frontman Mike Edwards on selling out vs. cashing out:
We didn't hesitate to accept the offer [to play at a corporate conference] and I can't think why we should have. I recall from my music-press-reading days that accepting money from The Man is wrong but I can't remember why, or how it differs from signing a recording contract or playing a heavily sponsored festival.
Like other teens, when I was younger I formed a notion about the purity of art versus payment for art (this correlates inversely with the number of 15-year-olds paying mortgages) that made it an Offence In Rock to accept an honest month's pay for an honest three minutes' work. Even then there seemed to be some contradiction between punk ideology and the Great Rock'n' Roll Swindle.
See also Dave Eggers' famous sell-out rant in his interview with the Harvard Advocate.