Mars wrote in Interesting Non-TSR Items Formerly on eBay:

Badmike wrote in Interesting Non-TSR Items Formerly on eBay:A lesson for all "investors" in this stuff that a hidden hoard is just inches away from heavily devaluing your collectibles!!!  Lets face it, for a lot of these rare items scarcity is the main factor driving prices....unless it's a Starstone or something similar, it wasn't the stellar writing/artwork that made them expensive.

Absolutely good advice.  There are a few of us out there trying to track down authors which sometimes turns up boxes of stuff that never sold and other times maybe only a couple copies, etc.  I usually feel it only takes 4-6 copies to drop the price a significant amount.  I have probably contacted 30+ small press authors with maybe 15 still having various amounts of their books around - sometimes 1 or 2 othertimes 50+ copies.