Beach Audio via eBay is selling the Synology DS218+ NAS for $325. Using coupon code POPUPSAVINGS decreases the price to $277. Shipping is free. Sales tax not collected in most states, see seller details for more information.
Link: https://www.ebay.com/itm/Synology…rk:2
This NAS is able to handle plex 4K transcoding with a Plex Pass and Hardware Acceleration option enabled.