What may be the value of an unopened LP of a major star from the time before he became a star?

A colleague of mine (not a friend, which is important in my story) bragged the other day he'd found a bunch of brand new and sealed vinyl LPs in his brother's basement which, I think, may have included Kid Rock's unopened "Triple Maxi Pad 12' " vinyl LP. My question is: what value may something like this possess? I'm not a huge Kid Rock fan but like his now-infamous song "Yo-Da-Lin In The Valley", the history around it and would definitely like to lowball my colleague on the price but (because he's a good collegue) not to the point of offering a ridiculously low price. Thanks.