If you are interested in calling more for a lower monthly cost you may want to consider looking at the O2 SIM deals that are available. If you have an unlocked mobile phone that is GSM capable you can take advantage of lower priced O2 SIM deals that cost less because you do not need to pay for the phone.
You can find many different deals that have 30 day contracts. They start at 10 pound for 100 minutes and unlimited texts. For 10 pounds more you can add 500 MB internet coverage.
For 15 pound you get 300 minutes, unlimited texts and unlimited landline or O2 to O2 calls. For 20 pound you get 600 minutes, 900 minutes for 25 pound, 1200 minutes for 30 pound and unlimited talk time for 45 pound. Internet access is 5 pound for 500 MB with the 15 pound and 20 pound plans. You get 750MB for 5 pound with the 25 pound and 30 pound plans and 1GB with the 45 pound plan.
Twelve month plans often get you more minutes and data for less of an investment. O2 SIM deals with 12 month duration are priced at 15 pound for 600 minutes of talk time. Internet access is an additional 5 pound for 500MB with this plan. You can also find a 20 pound plan that gives 900 minutes of talk time and 750MB of data is an additional 5 pound. For 25 pound you get 1200 minutes of talk time and for 40 pound you get unlimited talk time. Texts and O2 to O2 or landline calls are unlimited. Internet access is 5 pound for 750MB with the 20 pound and 25 pound plans and 5 pound for 1GB with the 40 pound plan.