Good place to buy a new car specifically a BMW???

I'm 18 and my parents are about to buy me my first car and I'm thinking of a nice, used BMW. I am from Canada and used BMW's can be overpriced here but a few people I know have been getting very good deals in the states. I would like a 3 series coupe specifically but does anyone know what states have the cheapest car markets or where I can get the used deal on a used BMW? Thanks :)