Why don't you try Skype? Skype to Skype calls are always free, and calls to most of the world are about two cents a minute. All you have to do is put in about ten Euros at a time when your balance gets low. There are USB phone handsets for about $30 and adapters to plug a regular phone into. You can also buy a phone number for inbound calls (including overseas numbers, very cool; you can have a London or Hong Kong number if you want) for €30 a year. It's not free, but it's cheap enough and no worries.