How to activate cellular data on iPhone 4S?

I've tried everything anyone as said to activate cellular data to make my phone work when I'm not connected to Wi-Fi. I've reset the network settings, I've toggled with the Wi-Fi and airplane mode settings. Nothing works. How do I fix this because I can't use apps or safari when not connected to Wi-Fi.

You have to have a data plan with your cell provider to get connected when not on Wi-Fi.