Pair of
Coherent Medical I-90's with PSU's for $600 total... Located in California. If anyone is thinking about bidding, I'd suggest heading over there with an oudin coil to test the tubes first. But if they're in good shape, $300 bucks a piece for a PSU and tube that will probably do 4 to 5 watts (all lines) is a pretty good deal. Of course, you need 3 phase power and water cooling for these.
I recently tested a couple of these units down in Florida, along with a bunch of other stuff. (And yeah, we ended up buying all of it. Only one tube out of 7 was bad.) It's really hard to see the glow on these tubes, and you need to disconnect the tube from the PSU before you zap it or you won't see anything. Just remove the cathode wires and zap it on one of the cathode leads. Look down the bore and you'll see the glow if it's good. (It's very hard to see it through the sides of the brewster stems, because they are made of quartz and are frosty, not clear.)
Adam