I’ve seen perfectly good sofas sell for $1 (that’s one tiny little dollar) at estate auctions.
Estate auctions are great places to buy older furniture and antiques. That is where the antique dealers buy. I bought my first dining set at an estate auction. It was made by Ethan Allen. I also bought a bedroom set for $400. Brand new it would have been thousands. Generally if solid wood furniture has lasted 50-100 years, it will probably last your lifetime.
I would be a little scared of buying upholstered furniture because you can not tell if it is infested with fleas or bedbugs.