My friend and I paid $25 each (taxes included) for trial week at Bikram Yoga Dix 30. It was my first time trying hot yoga and I actually HATED it at first but then went back and realized it wasn't so bad.
We tried calling the first time to take an appointment and no one picked up, so we just showed up and the instructor welcomed us in.
Check out my full review/pictures on my blog: http://arzanmontreal.blogspot.ca/2014/03/bikram-yoga-dix-30.html