Its Star Wars collectors that are buying them for a premium.
I pay £45 for any I find, used to pay £25. A mint one in box went for £160 plus not so long ago, on that site that cannot be mentioned. In truth its a bit of a lottery if you can find a Star Wars fan to pay a premium. A lot were sold and there are a lot of Star Wars fans. Must post to the USA.
It doesn't work with the round nosed ones, though many try.
There are better and more robust red dot sight systems for shooting.
Yours is the Day/night one; which will have lost its glow in the dakness. I prefer the clear. Both will still work. Often the front lens has a crack in them, which doesn't natter if not too big.