JoshDwyer:

Im probally way off... But my guess would be about 10 000 dollars.. I do gigs at my cottage at partys.. I 'll come out with a demo C.D to sell :P! After I get my keyboard I'll save to the penny lol! Then I'll invite everyone who can come!! Lol!

I was thinking two to three times that amount.  Transportation, equipment, the crew, venue plus all the bands other costs like food and rooms. 

It is an interesting idea. I heard that its actually possible to book Paul McCartney...for 4 million dollars a night.