Some observations made by a librarian and collector:
The prices of used books are always a question of offer and demand.
New books (some 20 years out ot print) might be more expensive than older ones in sufficient number.
There is also the question of damage. The binding can be repaired - you also need new clothes sometimes, if only the book is readable. It's like a pretty girl whom you appreciate even without cloth(es).
An example for readability:
The book from 1650 I bought to celebrate my first salary was marred by a bookworm which ate away the lower part of a line. But everybody knows that the upper part of a Latin letter is enough to read without problems. On the back pages the tracks wnt exactly between the lines which were legible without problems. And after the first pages there were no bookworm traces.
So the antiquarian sold it for about (converted!) $20,-, I would have paid the triple because I had looked out for it such a long time.

Some of the items offered here are very interesting. Maybe they are not reprinted because of copyright or a lack of widespread demand.
Since they are from a folk collector's shelves methinks you should sell them in the folk (Mudcat) community, not to an antquarian who will pay you not much and sell them expensively.
Think of the poor folk friends in the cold!