Modern smartphones look a bit different than ones from just a few years ago: there's the double rear cameras, of course, but more pervasive is the fingerprint sensor. A fingerprint sensor built into a phone offers a highly convenient form of security, but is also becoming an important component in making mobile payments. While a fingerprint sensor is included on all the big flagship handsets, those tend to cost $600 or more. Can you get fingerprint sensor on a (much) cheaper phone? Yes, yes you can.