A smartphone that lasts 4 days with standard usage and an impressive 45 days on standby. Such numbers are quite rare with today's feature-packed smartphones. But that is exactly what BLU Products is trying to sell with the Studio Energy. And it's selling it with a very low price tag to boot. That is, if you are willing to accept some compromises along the way as the smartphone won't exactly have flagship specs. But if you're looking for a long lasting, affordable prepaid option, this might be it.