The hugely popular Renpho Smart Digital Bathroom Scale is an Amazon bestseller that tracks your stats like a pro, and it's just $22, down from $35, when you apply the on-page coupon.

And it is pretty inexpensive for a smart scale. You can get the Eufy Smart Scale C20 for $39.99 right now on Amazon. That’s a 33% discount compared to its normal list price of $59.99.

Smart scales can provide a lot of data before just a regular scale, and in a way that the average user can easily read it, but how exactly do they work?

The Eufy P3 smart scale is a well-designed scale that gives detailed health insights at an affordable price, but in testing we found some of the tech is lacking.