I charge $125 an hour for flight, ground, sim, or consulting time.
I probably take home about $0.10 per hour worked.
While we don't charge for maintenance cancellations, depending on how it was discovered, there might be a ground time bill for some portion of the process leading up to said cancellation. The before flight instruction, the preflight inspection, taxiing, obtaining mechanic 2nd opinion, and obtaining maintenance processes are all learning opportunities and one's certificates are at risk for it.