I bought a 12GB Three data sim card in the UK the day before leaving for the Lana, valid for a month, which cost about £20 I think. I have a dual sim phone so for the very odd phone call, I used my normal sim. With data roaming, it made sense. The new sim worked perfectly for the entire month practically everywhere, so much so that I only hunted down and used wifi when I wanted to use Skype. The rest of the time, I was doing general browsing, email, route finding and photo stuff. I was amazed how fast it almost always was (mostly 4g). I used to compress photos before sending them anywhere, using an app called LitPhoto (Android Google Play store, but there are lots of apps that do the same thing). The process of getting a data SIM in the UK was a five minute job - it can take ages getting one in a shop in Spain!