How much do I pay for my internet on iphone 4 and T-Mobile company per month?

Oh well my dad FINALLY bought me this iPhone 4 and he doesn't really know that I have internet on it he probably will know when he sees the bill so I wanted to ask how much do I pay each month for using the internet on my iphone cuze in that case I can save up money every month and give it to him for the internet and I just use my internet for facebook, instagram and Vine. That's it. I don't download anything. So answer me with the best possible answer as soon as possible Thanks ^.^

Added (1). Btw my network is 3G. I just wana know how much I pay per month for the internet

Added (2). Btw my network is 3G. I just wana know how much I pay per month for the internet

Your usage is probably lessthan 512 MB per month,
so get your plan for 0.5 GB

You pick those options when buying the phone. Its not the same for everyone. Also in this case T-Mobile does not (in most places) have an iPhone friendly 3G network so expect 2G speeds.

Let's say you used about 500 MB a month, that will be about 50-100 dollars.

  • Is 40GB internet allowance per month enough for my household? In my house we have two laptops and two iPhones which are connected to the BT Home Hub. My brother and I browse the internet, we don't download games and rarely download applications (unless it's from the apple app store for my MacBook). Our browsing is quite heavy-use though. I'd say I spend around an hour every night on my laptop, and my brother spends around four hours. WIll 40GB be enough?
  • Iphone 5 owners? How much do you pay per month? Looking to get an iphone 5 with a family plan of two lines. Verizon offers unlimited talk and text and 2gb of data for both of us for $70 each. Is this a good deal? I pay around $60 for my basic phone right now.
  • How to pay 45$ per month with an iPhone5? Hi. I'm looking to buy an iPhone 5 with my upgrade. I'm on a family plan. My girlfriend pays 45$ a month and she uses data all the time, including unlimited texting. What would be the exact plan for this? I'm pretty sure my family plan gets unlimited texting for free, as well.
  • How much per month would an iphone cost me? I'm on a family plan with At&T and we have unlimited texting. How much would internet cost? (limited and unlimited) Also please explain 3G and 4G to me? I don't understand what that is… Does it cost extra?