>5$ worth of parts and 1~2 hours of labour :)

I think you're vastly undervaluing the cost of operating a auto shop + skilled labor. $700 was the cost for an auto repair business to 1) have a skilled technician find the problem 2) devise a repair method and 3) execute the repair.

Car repair is an expensive business to operate. Rent/building costs are high, lots of expensive equipment, one of the highest insurance rates around (you're lifting expensive heavy weights up and down over people all day) and labor is us usually relatively skilled and costly.