Check
resellerratings.com first. This place only has two ratings, but they both follow the same pattern as the other rip-off sites. Bait-and-switch where they take your order, then call to "confirm" and end up using aggressive sales tactics to strong arm you into buying overpriced accessories, or worse, charging you extra for things that should have been included in a retail package anyway (battery, charger, camera strap, etc.) After reading a few reviews for places that had deep discounts I don't even bother checking there anymore. If I'm buying new online, I go through B&H, Adorama, or Amazon (not the marketplace).
Something else to keep in mind is that Nikon only honors the warranty when the equipment is sold by a Nikon authorized reseller. You can check their website for the authorized dealer list to see if the place you're buying from is legit.