Alternately you can buy the phone separately. There are quite a few good deals around for both new (around £350) and almost new N900s. Then you can get a new sim only contract. I am on a SIM only contract with O2 and get 900 minutes, 1800 texts and unlimited internet for £11.50 a month(O2 used to have a 500mb fair use limit but that was scrapped). So do the maths.