Pretty much all TVs are Smart TVs these days, but they're not the best supported devices out there. Maybe you'll get a couple of years out of them, and even then you might have to take some extra precautions to keep them secure. It's much better to have a smart device plugged in, since those generally don't have the same problems, and one of them has a hefty discount.
The Now TV streaming stick is pretty cheap at the best of times, with an RRP of£15 if you buy it by itself, but this one is already cheaper at £11.58. The fact that it's bundled with a two month Now TV entertainment pass is just an extra bonus, since the two would normally cost £30 if you paid full price. In fact the pass itself costs £16 bought separately, so you're getting one hell of a bargain whether you need the streaming stick or not.
The stick itself has voice search and supports 1080p/Full HD output, but do remember that Now TV is still limited to 720p at the moment. Why? Who the hell knows, but at least you can watch whatever Netflix or YouTube have to offer in high definition at this price point.
Of course if you'd rather not be limited by the apps Sky lets you download, you can also take advantage of deals on other streaming devices before the end of the day. Amazon's Fire TV Stick is currently half price, and you can get a respective £10 and £20 discount on Roku's Express and Streaming Stick+ over at Currys. That's not to mention all the deals on brandless streaming boxes over on Amazon, if you're feeling brave.