I use IB and buy with CAD, the current cross is .98302. Most of my trades are $1. For instance, if I want to buy 100 shares of a 10 dollar CAD stock, it will cost me $1.
The most I've paid is just under $5 to trade $800 worth of a CAD stock that was under a dollar. They have some funky price schemes, but I don't really care since all of my trades end up being lower than any place else except for Zecco which is 10 free trades per month with a 25k balance, which I have there as well.