Cell phones are well worth it for kids. When I have one and he has grown, he will definitely get one...so I can get ahold of him when needed! It must stink to be a parent and have no clue where your child is.
Oh, and paying for unlimited texting is worth it, if you tend to go over. I pay $20 extra a month for unlimited picture texts, regular texting, and internet....and I think it's worth it...especially since I went over my limit when I didn't have unlimited, and ended up having to pay $120 in fees.