Wireing harness?/heater box?/Rear end

[old Chevy guy]

Im parting out a few trucks on craigs list.Sorry I didn't post them here but am hoping to sell some leftover stuff localy so as not to have to ship stuff. I have a guy who wants a complete wireing harness for a 72.It's big bucks new but how much is fair used in good to exelent condition? Another guy wants the iner and outer heater boxes with the core if the core is still good of course,Fair price? good condition. How about a rear eaton axle for C20 with coils? Thanks Frank