Anything over $100 for a DVD burner is way too expensive. The only one I know of that can justify its high price (and even then, only somewhat) is the Plextor 12x burner, which will burn DVD+R at 12x (it still burns DVD-R at 8x).
$84 is actually somewhat high for a typical DVD burner. That's what the Pioneer DVR-107D costs. It's $63 for an NEC 8x burner, and $76 for a dual-layer version of the NEC. The only thing is that the NEC isn't natively supported on a Mac.
It's easy to look at the specifications and get excited over features that really aren't useful yet. For example, although I have the Pioneer 8x DVD burner, I haven't bought any 8x media for it because it's too expensive. I just get by with 4x media. Also, there are a bunch of dual-layer burners out now, but they only burn dual layer discs in DVD+R format, and they only burn them at 2.4x. It takes about 15 minutes to burn a single-layer disc at 4x, so it would take 50 minutes to burn a dual layer disc at 2.4x. That's a really, REALLY long time.
I'd say if your neighbor wants to stay up to date, he should just upgrade to 10.3 and get the DVR-107D. NewEgg doesn't even carry the DVR-106 anymore, so you would have to overspend on one at eBay or something if you wanted a drive that is supported in earlier versions of the Mac OS. It's better to just get the 107 and use the hacked drivers if he doesn't get 10.3.