VNDS all the way if the price for a DS pair is too high. Scooped some '15 Aquas for $40 over retail I think (pretty sure MSRP was $200) and I don't regret it. Can't even tell they've been worn. If I'd bought em DS, I'd have been paying $400+ for my size 13.
I do agree though that there's a limit to how used I'm willing to accept. Blatant creases, chipped paint, et cetera, is a no go. If my shoes end up that way, it's because I wore them to that point, not someone else. As corny as it sounds, every major crease and scuff tells a story, and if my shoes are gonna tell any story, it'll be mine. I also simply refuse to wear someone's sloppy seconds. I don't need any shoe THAT badly.