SMS to email conversion app

By email I'm talking about an auto conversion to an email derived text. Example...555-555-5555@vtext.com so that it uses data we already pay for. Seems unfair that smartphone users have to pay a $30 fee for data and pay for texting on top of that, maybe it's just me. The big hurdle I could see in this idea is being able to recognize which carrier to use in the subject line. It'd need a database to compare number to carrier.

I'm aware of Google Voice but am looking for additional options. I would love nothing more than to call Verizon and tell them to cancel my BS texting charge.