I would like to know the value (how much someone is willing to pay cash) of used mint condition certified high-fidelity recordings such as:

Everest Hi-Fi Long Play. Mahler: Symphony No. 1 in D Major conducting the London Philharmonic Orchestra.

Columbia Masterworks LP.
Serkin. Brahms: Piano Concerto No. 2/The Philadelphia Orchestra/ Eugene Ormandy.

London FFrr.
Delibes Coppelia.
L'Orchestre de la Suisse Romande/Richard Bonynge.