What happens when I turn off 3G and celluar network on iphone?

I just went over my internet usage and I have more than 25 days remaining, it has already charged me about $30. If I turn off 3G and celluar network, does that mean I won't have access to the internet, meaning that it won't charge me. How does that work?

That's is correct you won't have access to it until you turn it back on

Yes, you wouldn't be able to use the 3G network & you wouldn't be charged.