Okay, here's the situation. I've got two phones with AT&T on the unlimited data plan, and we each have the $5 text message plan with 200 messages. Simple enough, and it works for us. Getting my son an iPhone 6 for Christmas, however I cannot add him to my plan unless I give up unlimited data. Not going to happen. So, he's getting his own plan with 3GB of data, and his own number. Now I need to figure out texting options. AT&T doesn't offer the $5 texting option anymore…and $20 is insane, especially for a kid. He will want to text with his school friends, but not everyone has an iPhone. And not everyone has AT&T. I've done some searches, but my results are vague at best. So I turn to the collective….are there any apps that seamlessly allow him to text to friends with different carriers, and receive texts on his phone? With his 3 gigs of data, will this be a limiting factor?