Where are some places you find good deals? I've seen Craigs list had a few but do you have any other place to look?
For
used gear, Craigslist and eBay are a start. Also, many of the scuba forums, including SB, have sections where divers post used gear for sale. I have used one of those to buy some tanks before - fair price, got what I wanted.
The emphasis in flots am's post is not so much on 'where', but 'how'. Do your home
work on gear, and decide what you want, based on the kind of diving you are most likely to do - down to the specific brand(s) and model(s) you are willing to consider. Doing that work also includes finding out what brand service is available locally Then find the best online price for new equipment of the brand and model you have decided on, and use that price as a benchmark. It may or may not end up as what you pay when you buy - you may decide to pay considerably more, because there is additional value in a particular transaction. But, if you know what you want, and what a fair price is, you have a better chance of spotting a good deal when it comes along. My standard for used gear is never pay more than 50% of the lowest new price I can find. I usually pay much less. But, I let A LOT of things go on eBay because the bidding becomes ridiculous. And, that is where the 'patience' piece comes in (I may refer to it as 'discipline' but the point is the same) - be patient, wait until you find what you want, at the price you are willing to pay.
I have only regretted a scuba purchase on eBay once - I didn't do my homework (primary issue), and I wasn't patient (compounded the lack of background work). I have regretted a few purchases at my LDS, but not many. And, again, my regrets were based on my own failure, to do my homework and to be patient / disciplined, not on dealing with my LDS.