There is the Digicel international plan. A lot of locals have the plan - it costs ja$1 a minute - which is less than a penny and a half per minute us$. That is about as cheap as it can get...
you can send the top up to the person online at the digicel website, then they can purchase the international plan with that amount.
if you sign up to digicel they will also alert you to all kinds of double bubble promos, but that is for local calling.
"I beseech thee, my lord , let this venture be mine..."