First of all, don't get too excited because this phone will almost certainly never be available where you live. Regardless, the new Nokia 105 lasts freaking 35 days on a single charge and it costs under $20.
The phone isn't intended to replace a smartphone. Quite the contrary—it's for emerging markets, aka countries where millions of people don't own phones at all, including China, Nigeria, India, and Indonesia. One charge has endurance for 12 and a half hours of talk time, but otherwise the Nokia 105 is very pared down. It basically just makes calls (over 2G), sends texts, and has a few games. Otherwise, it lacks a camera, has just a 1.4-inch display, and looks much like your very first Nokia brick phone from 10 years ago. But that's exactly what it's supposed to be, and that amount of talk time in a place where you probably don't have access to charge all the time is essential. And if we ever saw it in the US, it would be the ultimate burner phone. [Nokia]