metal gal, you made me to be mean.
why are you asking such a stupid question? 
skype to skype, it's free. don't you get that? 
now what more free you need than that?
don't you know how PSTN works and how these switch tower operates. they all cost money.
literally and in true sense, even skype-2-skype is not free. It uses up your internet for which you pay money.
At the end, there is no such free things okay? so stop being stupid and you won't get picked up like that.
bewkoof ..