Something about exceeding my data allowance under my Verizon family shared plan?

So here's the deal: I have a family plan with 4GB data plan and unlimited text and call which costs 50 bux per month, but what happens if I exceed the total data allowed? I'm a iphone photographer which requires me to constantly upload photos to Instagram almost everyday, and I'm really afraid of being charged a lot if I exceed the total data allowed…

If you go over on Verizon's data plan, you will be charges $15 for every 1GB of overage past 4GB…

Example, at the end of your billing cycle, you rake up 6.29GB of Data… Thats 2.29 in overages… Round up to 3 so it covers that 0.29GB usage… So 3x15 = $45 extra on your bill

  • Will this add to my 3G data allowance? On my iPhone 4S on the settings tab where you turn on your 3G there's a button to turn Cellular Data on/off and another button for my 3G. If I only have cellular data on and not 3G will it add to my contract bill because all I have is 100MB so I really don't want to go over and pay more than I already have to so basically if I have cellular data on will it eat away at the 100MB I have?
  • Will 4GB shared data be enough for two iPhone 5's? I'm signing up with Verizon today and getting two iPhone 5's. On average, is 4GB shared data per month enough to compensate for both devices?
  • What is Data Allowance (Verizon)? I have an iPhone with unlimited texting and the cheapest data plan. What is data allowance? I keep on getting text alerts telling me that I've used 50%, 75%, 90% of the data in the pats two days. What is it? What am I doing on my phone that is making this dumber go up? Is it Wi-Fi/ 3G usage? Can someone tell me so I don't get charged for going over.
  • What is 1GB of shared data for iphone 4? - 1 Ok i might get an iphone 4 from at&t that is 8GB, but when i went to the mobile share plans there's a thing about 1GB of shared data with unlimited talk and text. My question is what is shared data? And the examples of using it? And how much does is 1GB to be used?