Originally Posted by mdonova33
Are the best deals usually on the Head-Fi classifieds? I assume eBay is a no no...
Also are most electrostatic headphones good, or are there brands to stay away from?
Sometimes it's the Head-Fi classifieds, sometimes it's eBay, sometimes it's AudiogoN. You just have to look around and keep your eyes peeled, and in the case on eBay, hope that the auction you're gunning for doesn't have any overzealous bidders to compete with. I've already seem some vintage Lambdas sell in the classifieds here for $300 or less (excluding my own), but the required driver unit would have to be purchased separately, pushing it over budget.
For instance, here's an SR-Gamma that sold for $152.16 shipped. You'd need to find a replacement AC adapter for the SRD-X if you don't want to be exhausting C batteries all the time had you won that auction, but I'm sure it wouldn't be too difficult to source a compatible AC adapter, and the SR-Gamma uses the same drivers as the SR-5N and SR-X Mk3, from what I've heard (which means that it's quite good for a non-Lambda model). While it's too late for that auction, it may be worth considering the next time it shows up for sale somewhere for a low price.
Electrostatic (and electret) headphones aren't very common, and the majority of them are Stax. They're not the only manufacturers, but when they only make electrostatic headphones while others like Koss mostly produce dynamics with the occasional electrostatic, it's to be expected. As long as you make sure with the seller that there aren't any channel imbalances or other serious flaws with the set (most of which have to do with being several decades old more than anything) before you commit to buying, you should be good to go.