45's are very HOT right now! With sleeves some are outta sight. If you are planning on selling, I would do some research on each title. I have a magazine somewhere in the man cave with info from a serious collector of over 500,000 45's, I'll look for it, it has his contact info. Then there is always the Steve Hoffman forums as well.
Craig, very few 45s are worth anything. Stones and Beatles picture sleeves depending on titles are worth a few bucks but nothing outrageous with a few exceptions. I gave someone all my Elvis ones here in a bundle. The only 45s really worth a lot are obscure psyche, some soul and of course private label local band hard rock and metal. Zeppelin WLP's can be pricey if they come with picture sleeves. I have a lot of Zeppelin promo stuff, have to dig some out, I even have several of the mono WLP albums
A lot of country 45s were released on colored/transparent vinyl
Lastly, if you see heavy wear on the labels, that is usually an indication that they are played to death and will sound like shit. I have a couple cases full of mint shit, I doubt there is anything super valuable except for a few of them
It's a very narrow market out there and usually it's 60+ year old dudes that are into them still
Here's one I have out in the garage unopened, cool but not that valuable. When Ed was here, he saw a bunch of old WLP and other original release Beatles shit just hanging on the wall in the garage. They look cool but that's about it
Just play and enjoy them... I broke out Led Zeppelin's Hey Hey What Can I Do/Immigrant Song red label Atlantic for Deb the other day, she enjoyed it!