International carriers typically don't report for a month or two until after you've travelled, so there's no way to know what the roaming charge will be. The Canadian carrier will have to eat anything over 100 bucks, expect that to be passed onto the customers.
I think roaming should disappear - period. When I am in Europe - my Canadian SIM comes out and my Euro SIM goes in done. Everything is via Data now anyway. I am truly surprised that voice is still built into the phone - mobile companies should be providing SIP services to their customers and then that SIP service can be used from anywhere