>- Can someone living in the States buy Canadian competition
>licence? If yes, how? How much? Thanks.
Yes. You need to join a Canadian rally club ($30-70CDN) and then buy a license ($140?CDN for a National). Note that you cannot run SCCA events on it - as a resident of the US you need an SCCA license. Canadian residents can run SCCA events on their CARS license, just as residents of the US can run Canadian events on their SCCA license.
You need a CARS license to score points in Canadian championship events.