What you may be looking for is "Ships from and sold by Amazon.com". But there have been reports that even those products may be commingled with third-party inventory. (I don't have any personal knowledge on that one way or the other.)
Yeah, but in that case you're at least very likely to be getting the item you ordered. I've got the same policy for ordering stuff from Amazon - if it's prime and does from their warehouse I'll trust it. Haven't been burned yet, and the occasional mistake is always cleared up, usually with a 1 month credit to my prime subscription.
Amazon's prices aren't usually any better than local retail, or if so, not by much. The benefit to me is ordering an item mid-morning and having it on my doorstep by dinner.