Are you kidding me?

Well $50 seems reasonable but the true price of any object is what a person is willing to spend.. no matter how rich or how stupid. And I hope both people use them the one you sold it too and the one that payed that price. I can say it has been years since I have seen one of those but at any price if I wanted one I would take the lesser price. :)

Iv'e been looking for a reasonably priced Nikor 4x5 tank system for a couple of years now.
When I started looking sometimes they would show up around $100 or so, now $200 seems to be the norm. I'v pretty much given up finding one in within my budget.

I have one of these now; I paid about 85 for it about 12 years ago on Ebay. I use to own two of them
There are two variants at least; one 4x5 Nikkor has a faster filler cap. These tend to go for more money; many do not know their are two variants.
I have seen these vary all over the place: that auction is rather high; but not the highest I have seen either. I saw one for for about 290 about a year ago.
stuff like this varies. There are folks who really want stuff and really do not not to wait until another appears. It is a thinny traded item compared to a dumb 35mm reel and tank.
Odd NIKOR Stuff like 220 reels; 616/116 reels; 16mm reels; 127mm reels; 55 exposure 35mm reels; thick wire 35mm reels; 4x5 reels vary more than common 120 and 35mm stuff.

I didn't even know such a thing existed until this post. I've been souping my 4x5 stuff in batches in 5x7 trays, playing-card style. I can see how very cool this unit would be.

That's steep, but the price trend has been upwards. My first one was $150 in 2007, I caught a second in 2009 at a imprudent "Buy it Now" price of $24.99. I'll sell one someday.
The one in the auction isn't the later "quick fill" tank. Easiest way to get a quick fill tank that fits is to get the one for two of the large-size 220 reels. It's a little taller than necessary, so I throw a 16mm reel in the top as a spacer. The quick fill tank is a big plus for a tank this large.
The obscure Nikor items can go for big bucks. I've only seen one or two 118 tank/reel sets, they didn't go cheap. But I don't have any 118 film, so I was a spectator. I am lucky enough to have the 122 reel, and a lot of 122 film.

well, tomorrow I'm going digging for ebay gold in my attic, and basement. Maybe I'll find some other rarity. I do have an old Elwood enlarger, but I think it's in pretty bad shape, and shipping it would be a bear.

I do have an old Elwood enlarger, but I think it's in pretty bad shape, and shipping it would be a bear.

From what I've seen, print making materials don't go for very much - in general. Getting more than 20 cents on the dollar is very rare and you'll usually get less than 10 cents on the dollar - in some cases you have to give away working equipment. It's just not worth shipping.
All of the large format folks that I know scan (V700, V750s, and Nikon 9000s) and then print digitally.

As far as this tank selling for such a high price - all I can think of is that there hasn't been one listed for a while and folks pounced on it.

It was just dumb luck that the seller got so much.

Please send some dumb luck my way.

At a ham radio swap meet last February; one chap had a 1 cubic foot box full of 120 and 35mm reels and tanks.

He had it at first for 25 bucks; and at the end was 5 bucks for the entire wad; with no buyers. I have already a surplus of this stainless 35mm and 120 stuff; and had some of it on Ebay last winter with no luck. Thus I did not buy that box for 5 bucks; becuase I have already that and more in surplus.

The 5 buck buy would be a great deal for somebody just starting in film; but much of this stuff is really like old CRT's and dialup modems and Izone cameras; not worth the shipping costs to buy and resell.