Please explain Data Usage to me?

I have an AT&T iPhone 4S. Every month I'm not allowed to go over my 12GB data usage plan, and if I do I get charged for it. Well, today my mom got mad at me and yelled at me over how my phone bill was about 100 last month, and that it was because I had gone over my monthly data usage plan.
Originally, my mother told me "data" was only the 4G aspect of my iPhone, but now she has told me it is everything on my phone (texting, 4G, using apps, etc.). This seems like a bunch of bologna to me because my mom, brother, and sister's phones all aren't charged this way (they have all had their iPhones for longer than I have).
So, can someone please explain to me exactly what "data" or "data usage" is so I know what I need to limit doing on my iPhone each month?

IPhone 4S crashed? Help, please?

About an hour ago, My brand new, Black 16GB IPhone 4S was working completely fine. I just tried to check for notifications/text messages, and when pressing the home button it would not turn on? I had around 60% battery left on the phone.
I've tried:
-Holding the home and power button at the same time.
-Charging it.
-Holding the home button.

Any ideas on how to fix the situation? Any answers are better than nothing.

How to get iOS 6 for a regular iPhone 4?

My mom got a new iPhone 5 but she had a IPhone 4 not 4s. I'm trying to trade it for a pair of beats my dr. Dre. My mom needs to have a few stuff saved to icloud, like pictures. But is there another way to get icloud for iPhone 4 with out iOS 6 because whenever I go to settings>general> there's no software update. How do I do this?

Can I Use a Prepaid AT&T Sim Card in an iPhone 4?

I have an iPhone 4 (AT&T) if I buy a prepaid plan, and use a SIM card cutter to get the prepaid SIM card to fit into the slot, can I used my unlimited data/talk/text plan in my iPhone 4?
An attendant online told me the iPhone software is not compatible with prepaid data plans, so only the texting/calling would work, but I feel like she was just trying to get me to buy a post-paid plan.

Can You Connect a Sprint iPhone To Tmobile?

Okay So They Gave Me a an iPhone, but it's Sprint! And I have Tmobile. Does any One Know If its Possible To Change From Companies? Since the iPhone Dosent Have To Put The Sd Card?

How much money should i ask for a used iPhone 4? - 1

I need an at&t iPhone to use with the T-mobile monthly plan. My friend is willing to sell me her at&t iPhone 4 for $150.It sounded like a good buy considering unlocked iPhone 4's usually sell for about $350-450. The only thing that makes me hesitant of buying it was that she said the home Button doesn't work very well and the battery life isn't anything special. Should I negotiate the price with her?

If yes, how much should I ask for and what should I say?

How to block naughty websites on an iPhone?

Hi. I'm wondering if anyone knows how to hide apps on the iPhone or if there are any apps that will block "naughty" sites (or youtube vids) that are hidden apps? If it makes any differences, it's an iPhone 4S. Any suggestions would be great, as I've already set parental locks but I'm not sure any of them work for blocking bad sites, other than totally removing Safari and Youtube from the i-iPhone, which i don't want to do.
Thanks!

Added (1). To rephrase, in case I worded it a bit confusingly: are there such a thing as any hidden apps that will block "naughty" sites (or youtube vids)?

How to block naughty websites on an iPhone? - 1

Hi. I'm wondering if anyone knows how to hide apps on the iPhone or if their are any apps that will block "naughty" sites (or youtube vids) that are hidden apps? If it makes any differences, it's an iPhone 4S. Any suggestions would be great, as I've already set parental locks but I'm not sure any of them work for blocking bad sites, other than totally removing Safari and Youtube from the i-iPhone, which i don't want to do.
Thanks!

Added (1). To rephrase, in case I worded it a bit confusingly: is there such a thing as any hidden apps that will block "naughty" sites (or youtube vids)?