Using A Calling Card With A Cell Phone Using Cell Phone And Calling Card In Europe??????

Using cell phone and calling card in Europe?????? - using a calling card with a cell phone

If I bring my cell phone in Canada (which in other countries) in Europe, then I use a calling card for Canada, do not call to pay roaming charges when lyk 2.00 ridiculous? or phone cards and mobile phones only work if I try in Canada, go to Europe? CONFUSED
THX