HOW DOES THE IPHONE WORK WORK WITH TEXING?

I dont unequivocally assimilate how it functions and how most the devise is goign to come up as. Im formulation on removing the brand new iphone thats entrance out in july, singular devise but i wish total texting. That adds 20$ but does which embody regulating the internet? I meant it is the iphone. Youtube,, facebook,,, etc,,, is it usually free with wifi or would which nclude the 3g networking as well?