How Do You Price to Sell Classical LPs?

I know all about gradeing the vinyl and the cover, for jazz and rock but for classical LPs I have no clue on what to value them at. I just acquired an incredible 15 record set with 256 page book of Ludwig Van Beethoven Bicentennial Edition 1770-1970 put out by Deutsche Grammophon and performed by the Berlin Philharmonic Orchestra under Herbert Von Karajan. These are in mint to mint- condition and sound supurb. I don't know if I want to sell them or not, for they really are a treasure. I would like to know what they are valued at monitarily.
I'm not sure of the value of that particular set. I can say that I have listed and sold many records on this site, and have had terrible luck with classical lps. I have listed some NM condition Mercury Living Presence Stereo and Mono, and similar RCA Living Stereo "Shaded Dog" types, and asked probably only 20% of their book value, and they sat there like a rock. After I found that I could not even get a nibble on these for the paltry $10-$15 I was asking for them, I just put them back in my collection. Shortly after that, I stopped listing any records for sale. If your experience is anything like mine, you will have to give them away for far less than they are worth. My advice is to keep them.
I have had somewhat better luck than Twl selling lp's on eBay. Still, it is often the luck of the draw. And right now it is very much a buyer's market.
Selling classical on ebay as I figured, you need sell groups of 4...5 records so that buyer saves on shipping.
My 2 cents. As an occasional LP buyer, I see buying LPs as an alternative to music not available on CDs (either out of print or simply not issued), or as a cheaper method of acquiring "new" music.

SO ... I would obviously not pay more than USD 10 or 15 for RCA Living Stereo or Mercury Living Presence LPs -- I do have more than a dozen of those CDs, most of them bought used for around 5-7 dollars.

With that in mind, the Karajan Beethoven cycle is "worth" maybe 25-30 dollars (I think you can get a new 5 CD boxed set of the same recording for around the same price, if not less). I'm sure there are collectors/vinyl freaks :) that are willing to pay a premium for good condition LPs, but I'm just not one of them ;)