Hey Captain,
Sorry, don't have an answer as far as a resource for you. LP's are worth whatever a buyer is willing to pay for their 'sought-after' stuff. Condition of the albums would obviously be a factor as well.
If you have any Electric Flag/Nick Gravenities/Michael Bloomfield stuff in good condition- send me a PM. Or any Funky Nassau; Strokeland Superband; Doctor Funk; or Ambergris?-Amergris!.
I'm good to go on most other stuff from the late 60's thru early to mid 70's.
Hell, man- you really oughta just keep 'em- and invest in a super vinyl rig to play 'em. Vinyl still sounds more natural, you know..
WEEZ