Autoplay video and mobile bills

Money Saving Expert:

As playing videos on a phone or tablet via a mobile network requires the internet, it eats into your data allowance at a rate of knots, and once the allowance is breached, it becomes mega-expensive. Networks charge up to 20p/MB in the UK if outside your inclusive allowance, and up to £8/MB abroad to use internet data.

An interesting reminder about how the little things that we don't think twice about can be a huge deal for real world users.