Woot via Amazon [amazon.com]
has the Samsung U28E510D 28" 4K monitor for $229.99 shipped.
Warranty is 90 days. Sells for around $350 new. $5 more than the recent deal directly through Woot, but Amazon offers an easier return process, Amazon/Discover card holders can earn 5% cash back and a 3-year protection plan is available for only $16.13.
For reference: Amazon [amazon.com]
listing for new units with six customer reviews. Majority of customer reviews are at Costco [costco.com]