At Switchbird, we transparently use Twilio for phone numbers, voice and message delivery, simply passing through their costs to you with zero markup. So a standard SMS message costs a fraction of a cent, or $0.0075, per 160-character "segment. Messages longer than 160 characters will cost a little more since Twilio charges per segment. So, for example, a 320-character message (2 segments) would cost $0.015. Picture messages (MMS) cost $0.02.