I spent some money on getting the domain www.free-links.org the other day. I figured it'd be great for a directory site that wants to target the highly searched keyphrase "free links". I've been told the domain is worth nothing though because most people want to sell links at some point.
I wouldn't pay the registration cost. No offense, I just don't see any value whatsoever. The most you could hope for is AdSense revenue, and despite what most people wish was true, that just isn't very lucrative.