Here's the biggest piece of******I have ever encountered with Verizon. I have share everything. I usually use 6-12GB/month. So far this month I am over 20GB (appears to be the fault of a program called My Radar (or similar) and Win8 which ran non stop no matter what I did. It was burning about 3MB/hour. In any case, I finally figured it out and needed to raise my usage from 20GB/month to 22GB. Well.....it turns out that Verizon allows 2,4,6,8,10,12,14,16,18,20 and then 30GB for an extra $150/month. No way to add 2 more. You either pay the $150 or you pay the overage rate of $15 per GB.
I already got screwed for an extra $80 this month (I know, my fault I guess) and then Verizon rubs a bit of salt into the wound by not allowing me to adjust my usage to my needs, only their greedy demands.