Quidco is offering £50 cashback for a connected SIM only purchase through Dialaphone.co.uk .
On going through to dialaphone via quidco, click on SIM only (left column), and choose O2 sims.
On the next page, there are 4 deals. The first one is for an O2 sim with a 1 month contract length offering 600 minutes and unlimited texts per month for £10 a month for four months. (After 4 months, line rental is £20). Free to buy and free delivery.
Quidco mentions that cashback will be paid if the sim is active for at least 2 months.
You can cancel with 30 days notice after three months and voila, you have had the sim for 4 months, free to use the inclusive minutes and texts. You will also save £10, because cash back is £50!!.
This will be good for those with a handset which is unlocked and free to use for a new O2 sim. Limitation will be that you cannot keep either your present number or keep the O2 number when you cancel. Perhaps for those who are on a pay as you go SIM at the moment and want to have the free minutes and texts for the next four months.