Trading US stocks in Canada

I'm pretty new to trading and I was wondering if I'm gonna lose money when I invest in stocks on the NYSE or NASDAQ with CAD. I say this because a friend of mine trades through a bank and the exchange rate when buying stocks is higher than the exchange rate when selling (1.34 to buy and 1.31 to sell). Is it like this for all platforms of trading? Or are there some that have equal exchange rates when buying and selling?