How much would you pay for novelty? More than I would have guessed, that's for sure.
For as long as I can remember my main being 70, I would plant the toon in the DM Arena upon logging out, hoping that upon logging in, I would be lucky enough to find one of the rares that spawn there. Sometimes I would fine one, other times I wouldn't. But to give you an idea as to how the rares have treated me, my wife (whom I send the dropped items to for disenchanting) has saved up almost 150 Large Brilliant Shards in her bank. That's about 1500g worth according to Alla's "Most Common" selling price. Not bad, right? But it doesn't stop there.
I've also acquired almost 15 Orbs of Deception, a novelty item, and the main reason I stalk the DM rares. The Orbs sell very well on my realm, always being picked up on my first sales attempt (aka, I never have to repost the auction) and bringing in at least 300g - not bad at all for an item that in a functional sense, doesn't do a damn thing.
Farming the orbs, I financed my main's epic flying mount and am halfway through financing my wife's as well. But farming the rares has become a rather annoying task, with more and more people farming them to find an Orb for themselves or for financial gain. So, I decided it was time to speed things up a bit, charge more for each Orb I sell, and get my wife her epic flyer asap so I could put the grind on hold without much of a fuss.
After killing The Razza last night and acquiring yet another Orb, I posted the auction for just shy of 400g, about 100g more than I had been posting them. Not even a half-hour later, it was sold.
Needless to say, I was thrilled at the sale and prospect of selling every single Orb from that point on for an extra 100g. That's nothing to scoff at for sure, especially considering that it's about 1/12th of the cost of epic flight training. Not bad for a single sale at all, and I was so sure that I had done exceptionally well for myself that I headed over to Alla to check and see just how much more I had received for the Orb than was the norm.
Turns out, the most common price for the Orb is 200g MORE than what I was selling it for! That sucker is going for 500g. An item... that does nothing... 500g. Good lord, that out-casted Lower City item vendor doesn't look so bad now, does he?
So I guess there are two lessons to be learned by my experience with the Orb. First, always check the most common selling prices of items you're going to sell. Whether it's through browsing Alla or Thottbot or an add-on like Auctioneer or whatever, just check. And second, always, ALWAYS charge a bit more than the going rate for a highly-sought after and rare novelty item. Turns out people will usually pay more than what you'd hope for.