The people's Operator are offering Unlimited Texts, Minutes and 4Gb of Data for £11.99/pm via a 30 day rolling contract.
If you saw yesterdays SIM only deal from TPO and were perhaps put off a little by the price increase after the first 2 months, you may want to consider this slightly toned down version. It's £11.99 a month for unlimited calls/texts and 4GB of data. The differences with this deal over the "UK's Best Deal" is that you get 2GB less data usage, no £5 Costa Coffee Gift card and no introductory discount.
Both deals offer good value for money at this time, so i'd probably consider your data usage and go whichever suits you best. In the long term this deal will save you a few quid over the other rolling contract, which is great as long as you don't require the 6GB data allowance. You can of course cancel whenever you like due it being a rolling contract deal. Also don't forget to check your phone supports EE SIM cards, as TPO Piggy back the EE network.