Depend on their mood.
Know someone, who's a dickhead tbf, who went to a tyre place and got quoted £300 for four tyres and fitting.
Went away and bought four tyre from black circle for £200 and went back to the tyre garage, telling him he got it that cheap and asked him to fit it.
Garage charged him £50 a tyre to fit them/balance the wheels, new valves, and to dispose of the old tyre.