Can I talk to people In another country with a free call phone?

I want to know If I can talk to someone for free In another country If I had one of those free call phones for example skype?, do they have to have a free call phone too? for me to talk to them from the country I am In for free? I need to know so I can save some money but I need to know If I can talk to someone In another country for free and If they have to have one of those free call phones too? some shops like argos have free call phones like LG, skype etc but they dont mention If I can call anyone for free IN ANOTHER COUNTRY. ANY help would be appreciated and the one that tells me the right answer will offcourse be chosen as best answer. If you need to know any more details please message me.