I have some old Bibles that are written in, I think, German. They are copwritten in the years 1878, 1903 and 1920. They are not in the best shape
You might try taking them to Jackson Street Booksellers--they buy and sell used and rare books, and I think they are pretty knowledgeable. 1119 Jackson St, Omaha, NE 68102; (402) 341-2664. Or you might also search for similar items at bookfinder.com and amazon.com to get an idea of prices asked; once you have an idea of appropriate price, selling on Amazon is a very user-friendly process: https://www.amazon.com/gp/seller-account/mm-product-page.html?topic=200274530
If the bibles have genealogical information in them (pertaining to the families that originally owned the bibles), I would first try to locate descendants who might like to acquire them.
I hope this helps!