$250 for a cv boot is just about right, although I had a complete driveshaft replaced for $80 in labour plus parts. It's just much easier to replace the shaft than playing with a boot.
$500 for the brakes is way too high. $300 would be just about right ($160 parts and fluid plus 2 hours @ $80 per hour in labour). Are you sure the shop has any experience with Volvos?
BTW, although I like to work on my cars and get lots of satisfaction in the process (money saved count too) I don't think that servicing your car in a garage and paying for the service should be an excuse to be charged excessive prices, or receive a sermon on the values of doing the job yourself. Everyone enjoys cars in their own way. I like to own, drive, and work on them, but my friend just leases his cars, enjoys driving, and doesn't mind paying to have his oil changed. And it doesn't make his experiences any worst or better than mine, he just does other things while I'm getting dirty, and maybe in the process makes more money than I'm saving. And if repairing you car should be prerequisite to diving one then how about eating and growing your own food?
Happy planting :-)