This is only a problem if the service provider is a monopoly (or if every service provider illegally coordinates price fixing).
I might be willing to pay up to $800 to fix a $1000 computer (a more expensive repair might cause me to look to buy a replacement rather than repairing). But if it's a 1 hour job requiring $100 of parts, then all the computer repair shops would be competing with each other for my business, essentially setting their hourly rate for their labor. At that point it's like bidding at auction up to a certain point, but expecting to still pay the lowest available price.
So the problem isn't necessarily perfect pricing information from the other side, but lack of competition for pricing from the other side. We should be fighting to break up monopolies and punishing illegal price fixing.