Why can't I use my iphone without Wi-Fi?

I have an Iphone 5 with virgin mobile, and the only time i can use it is if I have Wi-Fi. For instance if I go out in public, I can't use Instagram or Vine, or any of those apps. Even thought i have excellent cell service. Is this the phone, or just simply the phone company? If it is the phone company can you maybe direct me to a good company that won't burn a hole in my wallet?

  • Why am i able to use the internet in s3 without service? So i just switch to an iphone 5c and been having my galaxy s3 with no service for a month and decided to turn it on and notice that everything that needs to be connected to Wi-Fi is … Show more
  • Iphone sim card? Can iphone use Wi-Fi without it? I have a iphone 5 that does not have service. It's my friend's old phone from Verizon, he upgraded to 6 and gave me the out of service 5. With that being said, does it even need the sim card? And can it still use Wi-Fi with no sim?
  • How to text and use iMessage on an old iPhone 4s without having to use Wi-Fi? IIm getting my phone taken away for a bit and I want to be able to still text or iMessage on an old iPhone 4s. My friend can use his old iPod to iMessage but he has to have Wi-Fi. How can I do it without having to use Wi-Fi or how can I at least set it up on my iCloud?
  • Can I use the Nike+ system without an iphone, ipod etc? I'm very interested in the Nike Lunar Hyperdunk 2012+ shoes for the nike+ system which it provides. However, I do not own any apple product. Is there any way I can use the nike+ system without an Iphone, Ipod etc? I do have an android, is nike+ available for this?