My brother has just given our dad his old 2G iphone after upgrading to the 3G one. Initially I thought he would have to pay £35 a month for the iPhone tariff, but it turns out that you can use the old iPhones with any o2 tariff.
There are a number of sim-only Simplicity tariffs, that have short term 30 day contracts, and these start from £15 per month. You can then pay £7.50 extra a month for unlimited data, or £10 a month for unlimited data + wifi.
In the end he opted for the Online 15 tariff with the web+wifi bolt on. This gives him:
- 200 minutes
- 400 texts
- Unlimited O2 to O2 calls
- Free voicemail
- Unlimited data + wifi
The only thing he doesn't get his visual voicemail, but not bad for £25 a month.