Answered question
If I lost my sim card, do I need to pay to get a replacement or I have one free sim (a form of warranty)?
I don't think you can have a free one because of you lost it.
Other answers
You have to pay 5$ (+ taxes) again.
To the best of my knowledge, no cell phone company in Canada offers a warranty on sim cards. Some would give free sim cards as a promotion for new activation.
For Fizz, you need to buy a new one.
You lost it, you pay for it