http://www.hughski.com/
If you are also printing than you need to spend more money on a calibrator that works with both screens and printers.I can't tell you how huge the difference can be even on high end monitors. I had a friend that swore all Macs were calibrated and he got mad at me when I laughed. After we did the calibration he realized how wrong he was.
Also buy this: SpyderCHECKR 24 and use it as the first picture at any new site. Color correction within 10 seconds.
https://www.amazon.com/dp/B00LPS46TW/ref=wl_it_dp_o_pC_nS_tt...
So what is your thought on the Color Hug 2? http://www.hughski.com/colorhug2.html
I bought the first color hug and it is still serving me well but I really like the new color hug 2 especially the latency tool.
Oh, I haven't worked there for a few years, but someone I know already brought it to the attention of upper management(pointing out the fact that Amazon reviews for Spyder products literally tell people to use the Open Source libs) and they've basically just ignored it as a whole. Their products are cool, and there were a few great people, but the company itself was... I won't really go further into it. Alas, I haven't been involved in imaging in quite sometime so I can't really comment on Color Hug :/
Buy the cheapest Datacolor Spyder5(S5X100). The hardware is same between all the versions and only the software differs. Then get the open source DisplayCAL(https://displaycal.net/) that works with Datacolor sensors and other manufacturers. I calibrate my display once or twice a year. I also use it to calibrate my gaming computer and laptop.