I'd like to know too. I'm building an SMS project and the best I can get is around $0.03 per SMS (moonshado through heroku) and I'm not sure how I'll be able to make any profit at that price.
I'm looking at using CDYNE for texts. At volume they also charge 3c, but there's no distinction between networks with their price so you pay the same to text Nepal as you do San Francisco.