Mobile phone contracts anyone?!?

Hey :), I am currently with O2 and I am not on contract. I text a lot, and I have to top up �10 a month for 300 free texts, �15 a month for 500 free texts and �30 a month for unlimited texts. This month and like many other, I have topped up with �30 so that I have access to unlimited texts, but a lot of my friends who are on contract don't pay anywhere near this sum of money, and they also have access to free minutes and access to the Internet. Does anyone know of a contract that is reasonably cheap where I can at least have unlimited texts? Love from Jess xxx