I used 27Gb last month of 4G WiMax. That would probably be like 3000 VZW dollars. IF Verizon still offers unlimited, I'll bet it's in the 60-80 dollar range when they go tiered. I'll also bet that the steps are like one of those links showed like $10.00 for 150mb with them knowing 90% of people will go over that.
10.00 = 150mb
20.00 = 1Gb
30.00 = 2Gb
50.00 = 5Gb
80.00 = Unlimited*
*= Not to exceed 10Gb or data will be throttled back
Was that all on your phone? Or was that tethering or using a modem?