The standard per minute rate for long distance to Canada is $.49 cents /minute. You can get a International Long distance value plan for 3.99/month that brings that rate down to $.9 cents per minute.
As long as you have a plan for texting it will count against your allowance for domestic text messages.
Text messaging usage while outside of the United States is generally billed at $.50/message sent, $.05/message received. If you're not leaving the United States, then you won't incur any roaming fees on messaging.