Cancel Verizon text plan bc of IMessage?

I have an iPhone on Verizon and so do all of my friends that I text message. I use iMessage with all of them and I was wondering why am I paying $10 a month for something I don't use? I do have one friend I text once in awhile that doesn't use iMessage but has Verizon.
Can I cancel my text plan and just use Verizon to Verizon or iMessage to iMessage?
Fyi. I don't have Wi-Fi I just use the 3G, but I have unlimited data.

IMessage uses data. If data is not available or down iMessage (blue) defaults to regular text message
(Green).