If on Talk & Text: “Your plan includes unlimited messaging to anyone on any network in the U.S.”
If pay per use: "The text messaging charge is $0.20 per message sent, per domestic address (including Canada, Mexico and Puerto Rico), and $0.20 per message received. The charge for each message sent to recipients in any other country is $0.25 per recipient."
"The charge for Picture and Video Messages is $0.25 per message sent, per domestic address (including Canada), and $0.25 per message received.
