answer:OK I’ll take a stab at it. I will assume this is a commercial handyman and not a guy in the neighborhood with a tool box. The highest cost will be the service call and the time to get to your house, billing, scheduling, staff, insurance, truck, supplies on hand, etc. Call that $200 and includes 30 minutes of actual work. You didn’t say what he fixed. If it was the leaking stopper +$10 with markup 210 +tax = $225 If the valve assembly was replaced: +50 with mark up 250 + tax= 267.50 If something broke along the way, e.g. corroded pipe, add extra $90/hr. How’d I do?.