I'm trying to find an advertising broker in Canada. I want to advertise in Canadian mags like loulou, flare, chatelaine, canadian living. I heard it's cheaper to do this through a broker – anyone know any companies that do that?

If you look in the front pages of most Canadian magazines, for instance Canadian Living Magazine it will give a complete breakdown of Departments and contact people for them, including sales and on line sales, etc. If you are interested in advertising in any particular magazine you should find out what companies they deal with. and contact them. I'm sure you could get the info you need from the magazine staff.