I just got a replacement from Amazon for ~$20. It's the exact OEM and works fine. My original pen broke when I dropped my phone last week. Worst part was 2/3 was stuck in the phone and I had to use a couple of paperclips to pull it out. Took a while.
Yet another Note 5 owner who purchased an OEM version of the S pen which works perfectly through Amazon. If you do a forum search here you will find a number of posts with specific Amazon item numbers.