The offer, as reported by cordcutternews, was recently extended to people who bought a Roku 4, the company's first 4K-capable streamer, which launched last year. It entitles recipients to a $50 discount on the new Roku Ultra, which currently costs $130.
Roku makes the most popular streaming players in the U.S. and is perennial champ in CNET's reviews. It delivers Netflix, Amazon, Hulu and thousands of other apps with our favorite interface and search. The Ultra is the company's most fully-featured streaming device yet, offering access to not only 4K but HDR video, as well as all of the remote control-based extras found on the Roku 4.
Roku often runs these kinds of promotions, offering discounts on new players to current users. According to the article not every Roku 4 buyer will receive the discount offer.