I finally cut the cord from cable TV and while trying out Sling TV, they started a promotion yesterday where they will send you a free Roku Express (latest model) if you prepay 2 months of service with Sling TV. This model won't stream 4K, but it normally costs $30 on its own. The offer is about halfway down. Since it looks like I'll be sticking with Sling, I figure I might as well take advantage of the offer.
Product details of Roku Express: https://www.roku.com/products/roku-express