My dad worked for another of Charlton's subsidiaries. He brought some of the books home for me once. The comics, not the porn.
If he had brought porn home for you, think of how progressive he would have been. Sort of equivalent to the dad bringing the son to a prostitute, but without any fear whatsoever of the son catching an STD.
As for the novels, I paid 50 cents for
Dark Shadows through
Barnabas Collins and the Warlock, 60 cents for
Barnabas, Quentin and the Avenging Ghost (was it merely a coincidence that the price went up 10 cents when Quentin's name was added to the titles?) through
Barnabas, Quentin and the Grave Robbers, and 75 cents for what I could find of
Barnabas, Quentin and the Sea Ghost through
Barnabas, Quentin and the Vampire Beauty. (Back in the day I never came across two of the last batch, but I picked them up on eBay in the '90s.) And I also paid 75 cents for the hoDS novelization. And all of those prices were the prices as marked on the books themselves.