All items sold by Amazon are new and come with the manufacturer's warranty. Note, that they are a market place and other vendors participate, so you need to pay attention to see who the item is actually sold by. Items sold directly by Amazon are usually indicated as such. For example, it will read "Ships from and sold by Amazon.com." Amazon does not offer their own warranty, if you need extended coverage you'll have to buy from either Square Trade or Mack. You can buy Square Trade warranties directly from Amazon. Lastly, cameras and lenses have a 30 day return policy.
Actually....you are thinking its a discount. Its not. Pentax does not allow retailers to list any price except the MSRP. Check B&H for example and you will find its $65 LESS than Amazon once you add to cart (to check price). Good luck, enjoy!