Considering that I'm asking everyone else these questions, I should probably answer them myself!

I don't do this as a full time job - I do it on the side and as a hobby. 80% of my jobs are weddings and I will typically get 6 to 8 a month. The weddings are a full day job - I typically set up at 3pm and don't break down until 1am. I charge $750 for myself (and usually hire someone else to do the PA system - costs me up to $150), and $250 for each additional band member. I also do studio work for $25 an hour - and like you Dave, anything I make goes right back in!