$500 ? You might be thinking of something else.
The B&Ks routinely go for less than $100. Here's one. I doubt the seller knows how to operate or determine if it's working. Could very well be just fine. Fairly easy to work on if it does need some servicing.
https://www.ebay.com/itm/14424548636...AAAOSw0f5hZupo
I use the Sencore VG91 for the higher (44 MHz) IF.
Likewise, this unit could very well be working perfectly.
https://www.ebay.com/itm/22468660785...4AAOSw9CRhjEbv