Follow-up question - if looking on Craigslist, SB Classifieds, Ebay, etc. How can you tell the overall condition of equipment without necessarily having the ability to get it wet? What do you look for in the BCD and Reg specifically? Any tell tale signs to look for to just walk away?
tbone has pretty much hit the mark on BCDs and regs. If the BCD will inflate,
and hold air for an extended period it should work for you. Most divers don't have an IP gauge to check their regs, so the advice is good, but may not be practical for all.
Pictures can be a big help. Knowing the brand and model is important. As tbone also mentioned, don't buy gear that can no longer be serviced, even if it looks good and is in working order. If you see something on eBay / Craig'slist / etc., and you want to know more about it, post a note on SB
Over the years I have purchased A LOT of used equipment, both non-scuba as well as scuba gear - including backplates, wings, regs, lift bags, etc., on eBay. With two exceptions - both regs - I have had very good success with scuba items. In one case the second stage housing had a small crack. I don't know if the seller knew that, or just sold it because it was breathing 'wet'. But, it cost me $17 for a new housing and the reg was good as new. In the other case, the first stage had been poorly serviced, and there were some work to be done.
When buying on eBay in particular, check the seller listing to see if the item is being sold as 'No returns'. That may diminish your enthusiasm (although I have only had to return an item once). But, the main thing is, if you decide to bid on something, have a maximum price in mind BEFORE you start bidding, and stick to it. I love eBay auctions, and auctions in general But, I have seen some ridiculous sale prices, because a bidder decided s/he really wanted something, and got sucked into the frenzy of bidding which often occurs in the last hour of an auction. My maximum is generally 'no more than 50% of the lowest (online) NEW price I can find before I bid. I have walked away from a lot of items