I am sure everyone is going to have their own opinions and rightfully so. So here is mine. I have two teenagers 17 and 15 (step sons) that practically live on their phones. My 6 years old has a phone with 4 buttons, mom, dad, brother & grandma and a panic 911. Grandma's idea originally. She is the first and only grandchild on my side. I love it though! I can call her when she is in her room for dinner, so she can feel important that mommy is calling her and she pretends she is grown up like brothers. We talk at night just to say I love you and good night. When she goes across the street to her friends house she can call me to cross the street with her, neighbor kid was hit by a car so yes I am a little nervous and I was run over and the driver tried to leave in broad daylight. So back to my point... I understand the risks of numerous phone calls and costly bills however, I look at it this way I would rather hear that sweet voice on the other end needing me and asking 500 questions than not to ever hear it again! If something, god forbid, ever happened you would not want to blame yourself because you didn't get that darn phone. Both my step sons were about 12 when they got theirs. Adding a line is only $9.99 a month with most carriers. I don't want to influence you either way but i love it and she really doesn't use it much after the "coolness" of having the phone wore off.
Hope this helps and god bless.
L.