Lowest price ever according to PriceSpy. It's usually $45-55. (There's a Smart Band 6 also out and it's $75-85.)
I've got the Smart Band 4 and it's pretty good. You have to create a Mi account to access the mobile app that it syncs with, although you don't need your phone with you for the band to work properly.
Great deal. The band works really well and the straps are compatible with the newer Mi Band 6 ones too