I just realized something.
Since I added a unit to my shopping cart on each page (removing it after the test), and thus eliminated quite a few vendors when it came up as unavailable, I wonder if my posting the links led to people buying whatever stock any particular site might have had. I posted a few hours before you, JA, on a lazy Sunday evening here in the US. Anyone who had been interested in getting one for $50, even on the off chance they might find it useful in the long run, could have decided to go for it. (I have enough dirt that it didn't appeal to me, but it took me a little mental wrestling to not buy the really inexpensive one in the classifieds here.)
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When I'm considering a piece of gear, I've learned to *never* tip my hand. Questions like "I saw this on Craigslist for $20 dollars... is this a good price?" are a great way to bring a piece to everyone's attention.
Hopefully the OP checked in and found one of the units which were available. It would be a shame if he/she asked for the information, raised the profile of the piece, and then was elsewhere and thereby missed out on the benefit of having asked.
If not, well, live and learn....
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Edit: Ah, NortyFiner confirms my suspicions.