old public phones

remember phone cards? not those we buy n scratch to make overseas calls. it is the phonecard with value of $2, $5, $10 to make local calls and after each call, the remaining value will be indicated by a small punch at the back of the card. i miss those phonecards. where are those phonecard public phones? oh, and i remember when i was in primary school, frens will say tt they found a way to make free calls using public phones (coin type) by entering some code or something like that. i don't see those phones anymore.