Anyway to block someone from texting you on your iPhone?

Hi, My ex-boyfriend keeps texting me and it's really getting annoying. I've told him to stop, but he won't listen. Otherwise, I would have just turned off my phone right now, but I applied for a job, and I'm waiting to see if I get a call back on my phone. I'm a broke highschool student =_= So is there any possible way to block someone from texting on a iPhone 4S.

Jailbreak and install iblacklist from cydia.
or call att and ask them to block that number.