I pay on average $2.80 for 2 team bags sent to Canada, use www.paypal.com/shipnow

I seriously doubt it. Postal employees will sometimes check things that people drop off in boxes. But they have no reason to double check a metered sticker one of their own employees took care of. If it makes it past the counter, I would say you have as close to 100% chance as possible of it making it to its destination.

A bubble mailer to Canada cost $9.50. I would be ecstatic with $2-$3! As it is, I will only send stuff I can fit in a CD mailer because if I do it myself, it's less than $3.50, but you can only fit about 3 or 4 cards in one.