Check out the thread on the verizon forum about keeping unlimited data when you have a family plan.I don't use but a few gigs of data a month myself, but converting our three unlimited lines to a family share would raise my bill by at least $60/month - so, even paying the "full" $349 price, that $60/month I save by staying off of family share will pay for the difference over a subsidized phone in a few months. It's a no brainer for me.
http://forums.androidcentral.com/verizon/227608-instruction-how-keep-unlimited-data-verizon.html