Does the caller and receiver of telephone call get charged?

If I put a $20 pay as you go card on my phone, If I don't use the whole thing do I lose the remainder at the end of each month, or can they accumulate????????????????

What is the cost with PC mobile for texting from Canada to the U.S.?

How are minutes of connect time calculated, exactly to the second or rounded up to nearest minute or what?

All PC Mobile plans are Pay-As-You-Go or more commonly known as pre-paid plans.
View there plans from the link below:

Link: PC Mobile Plans