I figure good wetsuits can be had prices low enough new and last so long that why buy used unless you're truly hard up. (Initially buying a whole scuba setup is sort of a shock, but remember that you're likely, over the life of the gear, to spend more on trips, air, service, etc., and there are much more expensive hobbies.)
If buying new, I see it as choosing one of two ways, considering that different makers and different lines fit differently, sometimes a lot differently. So you buy from the local shop where you can try them on, or you buy online and be prepared to send one or more back to try another. The local shop had a sale, and it was almost to the dollar for the same suit online. For rock bottom down and dirty new, I've used TommyDSports. They're okay. I doubt, though, that there's any long term savings, since you normally get what you pay for, and they don't have scuff guards on knees and such.
It wouldn't bother me to ask a shop if they could meet or come close to the online price - of course, that would be before I took up their time trying them on for size. I have to pay the postage back for any exchange, and there's the nuisance, so it's a reasonable risk exchange to buy local. For reference, I'm talking about a Henderson 3mm Thermoprene jumpsuit, close to $200 online and my local sale price.
When buying rubber products (nudge-nudge-wink-wink), one really should know the age of the material, which seems to me a reasonable argument for new wetsuits.
