Get a Samsung S5600 for £9.50 on orange pay monthly. Monthly cost is £14.68, for 100 anytime mins and unlimited texts. This is on a 24 month contract, but if you go through quidco you get £150 cashback after 2 months of the contract.
It was enough to tempt me from PAYG. I spend at least a tenner a month on PAYG, so an extra few quid a month means i don't have to be tight with my texts!!!