Haven't perused old lots of Betamax tapes on Ebay in a while. They have gotten more expensive. Saw one that had the SWHS in the batch, (sadly over) but other auctions without such rare shows also got into hundred dollar territory. There seems to be more demand for old sporting events and news programs than ever, unless it's some archive with deep pockets going after these.
It's a total crapshoot if the tapes are actually playable, and still have what's written on the label of course.