You get what you pay for. With that said, $90 is very cheap and rare come by, especially since theres labour included.
If you are referring to a break replacement (e.g the break discs) including the parts $90 in my opinion is really cheap.
It is average if they just turn, not replace, the rotors.
That is too cheap, unless it's $90 per wheel. If it's for all 4 wheels, I would steer away from that deal. There is something rotten in Denmark. You could probably change just the pads yourself on the front wheels for $90. It's not hard if you have any mechanical inclination at all.
If the brake job only consists of replacing the pads which is all that's needed most the time, then $90 is a good price as a good mechanic can do the job in an hour and make money.
Only is they're using genuine factory brake pads from the dealer of the car. The problem is you are not sure what they're using which is usually a disaster.
$90 is a bargain--too much of a bargain. The only way a shop can make money on a $90 brake job is to install garbage pads. Read this article on how much a brake job should cost
http://ricksfreeautorepairadvice.com/bra...
At a auto repair shop that's parts and labor included. $90 ??? Fair !?