Originally Posted by Guava
Long story short, the cost may not be real, in fact, you can even make money with it if your bet turns out to be right given some time and market volatility.
You are not buying an "option" on the US/Canadian exchange rate. You have paid 2.5% interest conversion fee to gain ~1 month free interest. Some time before your account comes due, you WILL have to convert the US funds back to Canadian (with probably another 2.5% fee). If the exchange rate fluctuates in the right direction by over 5% over those 30 days, yes you can make money. If It stays the same or goes the other way, you are on the hook for a REAL loss.
If you want to play the currency options or futures market, there are much cheaper ways of doing it!