How to set Repair pricing

How do people come up with the pricing for repairs?

I want to start doing some work for a local games store but no idea what pricing to give him for repairs.

At the moment it’ll only be simple HDMI and small component stuff, but how do people set their pricing?

I set my by 2 points. 1 the difficulty of the job. 2 what others in the area are charging for the same repairs. In my area a few shops charge 120 dollars for hdmi port repair. I charge 60. Others charging 180 for Xbox one hard drive replacement. I charge 40 for 500gb, 60 for 1tb, and 80 for 2tb

Not a lot of people doing low level stuff like ports and SMD work. Was thinking around £50 for HDMI ports.
Guess I’ll get a feel when I start working on stuff, was going to look at local recycling center see if they have faulty stuff to work on and try fixing.