how much to offer friend for records

I have a friend who has a pretty big collection of jazz, classical and pop music. He is interested in my coming to evaluate and buy a bit of his collection

he's an avid valuable book collector and I have the feeling he'll have a similar outlook on records

normally when I buy a "large quantity" of old vinyl $5 - $10 per record seems more than reasonable for good quality unless they are obvious rare collectables,japanese imports, etc

he played them on a Linn Sondex so they didn't get typical abuse

ebay pricing doesn't help with some people high balling prices for a sales score

he's parting with his vinyl as he's been purchasing too many instruments (guitars and basses) lately and his wife doesn't want him dipping into credit

any suggestions on fair pricing would be helpful