I'd say $3000 is about top price for a working, complete unit. So subtract from that what it will cost to restore yours.
Note that internal damage can be severe if the vanes (which are a kind of phenolic) have failed, or the bearings.
Also, Judson made blowers for many different applications, so be sure that the one you get fits the car you want. The high port TR3 version was sized for 83mm liners, so you'll get less boost if you have larger liners installed. Be sure to get the TR3 installation instructions as well; they include notes on how to modify the advance mechanism and, as I recall, add a brace. I have a poor scan of them (along with a lot of other Judson material), but can't get to it just now.
Judson trivia: Although the oiler was made by Marvel, Judson specified to use engine oil in it, not Marvel Mystery Oil. There was a hokey sticker (which looked handmade) that they slapped over the Marvel sticker (and which usually fell off later).
I agree, probably not best for an engine you drive every day. If you want a blower to drive, I'd suggest looking into the Moss kit instead. It uses a much more rugged (and efficient) blower than the Judson.
A very useful accessory IMO would be a boost retard module from MSD or similar. The engine needs significantly less timing while under boost, but Judson's approach was to just limit timing altogether (meaning it was effectively retarded while not under boost). But that's just guesswork on my part, I've not actually installed one.
More info here
https://www.judsoncompany.com/_content/reproductions.htm including contact info for George Folchi.