Amazon is currently running a targeted promotion that allows select customers to buy a Fire TV Stick 4K for $29.99 using promo code POWERFUL4K. You can also try the promo code 4KUPGRADE. The savings code will only work for certain customers and there is no way to know who those customers are or why they qualify. The offer terms indicate that this is an upgrade promotion being sent out to customers who have previously purchased or registered a streaming device, but having purchased a Fire TV model in the past is not enough to guarantee you’ll qualify for this promotion. The promo code is set to expire on May 7th.