You can call customer service to add the $2 international dialer and LD saver to your current plan. Since this cannot be added via self serve (to prevent fraud) they should not charge the usual $10 service fee.
EDIT: You also have the right to remove it any time.
Hi Heather. Just wanted to add to Curtules' accurate explanation. As long as you do not live in Manitoba, the feature is available. MB customers are only able to use a feature like the LD saver for calling the USA, nowhere else.