Lots of things to look out for but remember this: if it's too good to be true, it usually is. Some shops order a larger quantity of equipment and would leverage on a bigger shipment to pass on the discounts. Some simply use it as an exercise to get rid of their old stock before it falls apart in their warehouse. Was at ADEX some years ago and a dive shop was selling their booties for some ridiculous price like $10. Naturally, there was a mad rush for it and the owner (who was an acquaintance) was laughing in the background about "how stupid" the customers were because he knew the booties would be falling apart soon. So, don't be penny wise but pound foolish.