Yes, many prices on Reverb are highly optimistic, but that is the same on eBay. I prefer Reverb, as the sellers seem to be musicians and studio inhabitants, not cutthroat merchants of dubious integrity. The overpriced items sit there for a long time. The reasonably priced items go quickly, even before we get into wheeling and dealing. The thing to do is set a watch (automatic search) on the items you want, and wait for one to appear at the price you have in mind. If you are lucky, and have reasonable expectations, you might not have to wait too long.
I have had several successful purchases on Reverb, all in good to excellent condition and not overpriced in my opinion. I have also had many good purchases on eBay. In my experience, most deals are good deals, if you are careful. The scammers are usually obvious.
I had one bad experience on Reverb, where I got endless excuses but the seller never shipped. After about a month of angst, PayPal refunded the full amount. Reverb said they WOULD have refunded to me, had I paid thru Reverb.
Always protect yourself, and be aware that there are always risks. Look at the seller’s length of membership and reviews. Also, search the photos to see if they were lifted from somewhere else using tineye.com