These are souvenir sets sold at the gift shop of the Denver mint with a medallion of the Denver mint as the "sixth coin".
They are collectible for what they are. The Denver mint produced these from 1972 to 1998 and the Philadelphia mint made a similar set with a different medallion from 1973 to 1998.
I don't know what the San Francisco mint did but I think they made proof souvenir sets in a similar packaging. Not sure about that.
I did get
SBA dollars in souvenir packaging someplace along my collecting path but I think I since sold them. I had the 1982 and 1983 from both Phila and Denver and they brought really nice money when I sold them.
Perhaps the prices realized were from spirited bidding between bidders that want to complete a run of these sets for their own collection?