We hired a handyman to help my husband install a new screen door. He was
here 2 and a half hours and charged $150. Does that seem fair to you?

What did you agree to pay before the job was done ? That works out to $
60/hr.

No it doesnt seem "fair", in fact no "handyman" should be getting that rate
but if you didnt specify in advance, he can ask for anything.
Whether you pay it is up to you if theres no pre agreed price or contract,
written or oral.

Would you walk into a store and buy something if you had no idea what the
price was ? I dont think so.

R