Ask Your Carrier
Credit: Getty Images

If you're lucky, your carrier will handle the heavy lifting for you with existing deals or packages for both overseas-based calls and international data rates that are exponentially cheaper than default international roaming rates. As of this writing, the best of these offers comes from T-Mobile, whose Simple Choice plan ($50/monthly) includes unlimited voice on your home country's network, plus unlimited data and text around the world. Endless data means free or cheap use of services like Rebtel while traveling.