Well, this is another article where the title kinda tells you everything you need to know. Right now, SMARTY (an MVNO using Three UK masts) has doubled their data allowance on their £15 package.
There’s no big contract (it’s a one-month rolling deal so you can cancel at any time) and you get unlimited calls and texts too. 3G, 4G data and no speed restrictions.
If you’ve got a phone that you’re happy with, just whack this SIM in and you’ll be done. Bosh.
Head to smarty.co.uk for more info.