You can pay as much as $90 for the genuine volvo part, or quite a bit less with Bosch cross reference or VW or aftermarket part.

You can also go to IPD and get an adjustable voltage internal regulator or even an external regulator kit (I put an external voltage regulator on the 87 760T and it's worked fine for several years...better than fine with H4 Euro lights....).

Or you can go to almost any alternator shop or volvo or saab or bmw dealer and get a brush kit for less than $10 (I paid $7 several years ago) and remove the regulator/brush holder and replace them yourself. It takes about a half hour to an hour for the first time you do it. You'll need a soldering gun or 125w iron and someway to clip/cut the bushings that physically hold the pigtails to the regulator contacts (I used a dremel moto tool with a cutoff wheel). The brush kit comes with new bushings that you crimp to the pigtails holding the brushes in the holder. Then you solder the pigtail/bushing assembly to the contacts.