DJ Promo 45's - Interest?

Over the years I have collected a bunch of 45's as I found them and bought a few at a time whenever I found them absolutely mint. I now have a total of about two hundred. The vast majority are rock and soul DJ promos with the same song - stereo on one side, mono on the flip. For the most part, the only drawback is the frequency with which one must change the record. Sonically, most all of these sound incredible. It is fun to compare the stereo and mono sides. Odd the ones that sound better one way or the other.

Does anyone else go to the trouble of spinning these kind of 45's and do you find similar enjoyment? Also, where can one find the value of these records? Not so much that I have an idea to sell, just that I never see prices listed anywhere except for "stock" versions - juke box versions, if you will, with two songs per 45.