I see that it has already been pointed out that seeds can be purchased at high times. While I don't know what the prices are like there for myself, it was mentioned that they are very high. I recently purchased a few seeds from Le Rock on St. Catherine near St. Dominique for my first grow. They were pricing at $10 per seed with their inventory in a small lock box behind the counter. They provided me with some print-outs of their strains and some information about them but no original packaging; rather my seeds came from a small vial. Regardless, I'm hoping that they are good seeds although I can't say at this time - they're only germinating, but looking good.
Also, there is a small "A-B seeds" company that I found based out of Montreal which accepts money order or checks. I thought about contacting the guy who runs that to see if I could make a cash transaction with him, but it's in Montreal either way.
Cheers