Best deals are typically open-box and factory second / b-stock.
My Schecter Omen Extreme FR was $100 less than a new "fresh" one because it's a factory second. The problem? A super tiny chip in the clearcoat on the edge of the trem cavity.
My Yamaha BB435 was $50 off as an open-box deal. When it arrived, I found one of the tuning keys was slightly bent - still entirely functional, but unsightly. I got Yamaha to send me a brand-new replacement tuner at no cost.
ETA: Oh yeah, and I just got an Arturia MiniLab MkII for $65 as an open-box deal - almost half the normal street price ($120). I've bought quite a number of other things in similar condition as well, but don't recall the amount of the discount for them, as most were years ago now.
Places to check for such deals:
- Reverb
- Sweetwater
- Amazon Warehouse
- eBay