If you don’t mind “tinny sounding” call quality and want free, there are ways to use a free service. These things tend to disappoint me as I look for quality over cost when it comes to call quality, but for quick conversations, this is an economical solution in today’s environment:
In a test, iCall was a breeze to use, if a bit tinny sounding. The app is free, as are the calls it makes, but with a few catches. People on the free calling plan will have to listen to an ad before a call is connected, and calls are limited to five minutes. A $10 monthly subscription saves you from hearing ads, gives you voicemail and other services like call forwarding and allows calls to go on indefinitely.
via App of the Week: Free Calls, if You Don’t Mind Ads – Gadgetwise Blog – NYTimes.com.