First of all, don't do that, Sprint sucks. The network is terrible. This plan also sucks.
Buy an unlocked phone, that will have all the benefits of an unlocked phone and the $30 a month Tmobile "wal-mart sim" plan. Buy a Nexus 5 for you, a Moto G for the kids, have unlocked no contract phones for less money for the phone, less money for the plans, more data, and a vastly better network. If you want a new phone, sell your unlocked phone that's not useless on any other network and buy a new one. If you hate the service, swap the sim for another carrier.
Or not. I realize you're already invested this, so you won't do any of that. But you should.
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Disclaimer:
To make a long story short, I don't take any responsibility for anything I post here. It's not news, it's not truth, it's not serious. It's parody. It's satire. It's bitter. It's angsty. Your mother's a *****. You like to jack off dogs. That's right, you heard me. You like to grab that dog by the bone and rub it like a ski pole. Your dad? Gay. Your priest? Straight. **** off and let me post. It's not true, it's all in good fun. Now go away.