If it's the evaporator you'll spend at least that much unless you do the work yourself. It's about the most expensive item on the AC list as I recall, and it's usually fingered when everything else has been elminated. Requires removal of at least part of the dash. I think it will loose coolant too. Otherwise, it appears to be a good buy, from what you say.
--
John Shatzer, '97 V90 @ 105K

If the fix for the A/C was as simple as adding freon it would already be done. I purchased a 96 last year w/84K for a similar amount. Unfornately it was winter and I couldn't verify my suspicions with the A/C. The bearing on the clutch was bleeding rust & while it would engage I couldn't tell if it would cool. After replacing the condensor & compressor I found the evaporator with a slow leak. I haven't tackled that yet but it's not going to be fun. Parts cost isn't that bad but labor will make this a no deal if that's the cause. Have them fix it or give you a price to fix it then reduce the offer by that amount. I'd keep looking.

I think I would try and get that car a bit cheaper with the AC problem. I went over to the s90 forum and reviewed what you said about it. AC in texas is not an optional thing so that has to work. Have you proposed to them that they fix it first or could you have the car looked at by an independent volvo mechanic? To me is is kinda fishy when they will knowingly sell a car with problems. What eles could be wrong with it? Are they offering any warranty? If the thing needs a new compressor or other major part, you are going to be down a grand for sure. These are nice cars, but they are not rare. If they dont want to do a bit better, I would leave it be with those problems.
--
97 S90 with 179K miles still going strong

It's very simple! Use a 3/4" square adapter in the tensioner hole to remove tension on the belt. Take off the old belt noting the routing and install a new one. Let go of the tensioner and you are done.

There is a revised belt that is longer and uses a new routing. The new routing as the belt leaves the crank going CCW is: A/C to Alternator, back down and around the idler, up around the power steering punp, down past the tensioner to the crank.
--
'96 965 with 16' wheels, 18mm rear bar & 204 HP cams at 122K