Novice with vinyl & tapes needs help evaluating

I was recently able to cherry-pick a friend's vinyl & prerecorded reel tape collection prior to disposal. I found some interesting things that, I think, may be worth something. Jazz, vocalists, and big band music from Miles Davis, Stan Getz, Frank Sinatra, and others. Mostly mono with some stereo. I also took about ten stereo prerecorded 7" reel tapes (7.5 i.p.s.) in their original boxes that are either classical or big band from the mid-1950s. Also, a small set of boxed 45 rpm recordings of Strauss waltzes in mono from 1950. The last item is in perfect condition. The tapes have issues, including some mold and uneven windings on the reel. The LPs vary from good to poor in condition.

My intention is clean them up, record to CD-R anything I like, and sell them to dealers. There is a quarterly record show/sale near my home, and the dealers will buy desireable recordings from show goers. However, I am afraid that I might get ripped off, since I do not know which, if any, of these recordings are valuable. I have no way to listen to the reel tapes.

Is there a resource, aside from ebay, I can use to determine the value of this stuff, as well as qualify their condition in terms that a dealer would use?

If anyone would like more details on what I have, just post here, and I will post details as soon as I can.

Thanks in advance.
You are worried about getting ripped off on selling music you got cheap or free from a friend you "cherry picked"? really????
Lurk eBay to find market prices, then offer your stock to a dealer at 40% less.

Alternatively sell the whole lot to me except the moldy ones. I will tell you what it is all worth :)
Chadnliz: If you inherited a piece of jewelry and wanted to sell it, wouldn't you want to get fair value for it? Also, I intend to split the proceeds with my friend who gave them to me.

lmin2u: I wanted to, but there was a lot stuff, and due to some repairs being done in my home, space is quite limited. There was a lot of junk, too, like holiday music, kids recordings, etc. I did take one of those JFK memorial LPs, though.

Thanks, Tobias. I was hoping there would be some kind of enthusiasts' site which allowed you to look up the value of a given recording based on its condition. I guess not.
You didnt say you intend to split any profits, but I think it is great you plan to.