It is amazing how many people don't actually get that being a photographer is a profession, and that a professional photographer costs money to hire.
I was at a gig, back in the day when there were gigs, and I was asked how much it would cost to shoot a live promo of a band. He looked staggered when I told him. He expected me to do it for a few drinks, so I asked him how much he earned an hour, and broke down the number of hours I would be spending working for his band. Two hours travel (there and back), a minimum of two hours at the gig taking photographs, then editing time (approx 5 hours). I rounded it up to ten hours. I ignored the delivery of images, cost of petrol etc etc. and then asked him if he would work that many hours for a couple of drinks. Boom.
You can buy my prints at Picfair