How do I only use the wifi internet because I don't want to use my mobile data because I don't have Internet on my price plan?
Well, if you are running iOS 6.0 or later.
The option supposed to be in Settings>General>Cellular>Cellular Data---Off & Enable 3G---Off
I think you'd better check the settings in Privacy>Location Services.
Some items in it need Cellular data like"setting time zone" and "Find my iPhone'.