with 3 already, 4 still in their teens (although 1 is on a mission and she turns 20 in March another is a freshman in college).
Money is always tight with 10 kids and the cost of cell phones for teenagers seemed way too much around the time that we were at that tipping point of really needing them and we had no idea what we would do.
When we found Ting it was great. Because we can have smart phones for our kids and not have to pay for a data plan by just turning data off on their network through an easy app/web interface. They can still do wifi at any location that offers it and can text/call. It really made it affordable to make sure our kids were not out of the loop on team/group communications or stranded because pay phones hardly exist anymore.
We are at the point now that if they are involved in any curricular activities as they enter MS (6th grade) we want them (need them) to have a phone.