O2 has a sim only offering like the other networks and it is called simplicity.  From what is on offer o2 have the most competitive deals and a full range of options that you can pick on any sim only tariff. O2 offers sim only contracts from £9.79 along with Vodafone this network has the cheapest starter sim only contract. The prices of o2 sim only deals:

£10 per month - 150 mins & 300 texts - More info

£15 per month - 300 mins & 600 texts - More info

£20 per month - 600 mins & 1200 texts - More info

£30 per month - 1200 mins & 2400 texts - More info

There is a list of benefits that you can choose when purchasing a sim only deal with o2 they are:

- Unlimited o2 to o2 calls

- Unlimted texts

- Unlimited web browsing

- Unlimited weekend calls

- Unlimited landline calls

- 200 extra minutes

- Unlimited Wifi