Originally Posted by LuckyR
...from which service?
Giffgaff. It's sim only, so if you can pick up a phone on the O2 network or unlocked, you can save around £25 ($40) a month. It's not a contract either so you can stop it at any time, which I like. My sister is on it too and she's in America for the summer, she just stopped it and will top up when she gets home to carry on. If she was on a regular contract it would of ended up costing her nearly £100 ($150) over the summer whilst her phone was not in use.
It's cheap, no data limits and you aren't tied into a contract. It's probably not for everyone as you don't get the free phone when you sign up, but if you already have a phone it's great.