Over the three years since it was released the device has seen numerous sales on Steam, where you could get it for as low as a couple of Great British Pounds. After picking it up for literally eight quid during a Steam sale, I used the device once, packed it back in its box and now have no idea where it is. Nowadays, Steam Link is available as an app for in-home streaming, so Valve is discontinuing the physical box.
However, it has pledged to continue supporting the Steam Link for those who already own one and want to continue using it in the future. It worked, but was incredibly cumbersome, especially if an unskippable Windows Update chose to rear its ugly head.
Steam Link is being discontinued, according to an announcement from Valve, along with news the hardware is sold out in Europe and nearly in the US. While the system will be supported with updated software, there will not be any more devices produced. Sadly, its days are numbered; Valve has announced they will no longer sell physical Steam Link devices after the current stock runs out. Valve also has an app that lets a smartphone function in much the same way, or steams the games to itself instead. This initiative included the SteamOS Linux distribution, Steam Machines running SteamOS, and then the Steam Link. Because of that, Valve seems to be ditching the hardware and moving over to mobile development exclusively.