Well, I don't know anything about the Canadian Dollar, or how it is doing in the global market, but the rules day say:
"10. international entrees are welcome. Please us the denomination of your currency, closest to 1 US dollar. (i.e. 1 Pound, 1 ERO, etc. etc.) and a max of 20 of said currency, before tax, or shipping. (i.e. 20 pounds, 20 ERO, etc. ) And, I ask, if it is at all possible, that you also shop only at your countries equivalent to a "$1. store". ( i.e. 1 ERO store) If there is no such thing in your country, please do your best to conform to as many of the rules listed here, as possible, pertaining to budget, and of course all of the other rules listed here would still apply."
So, I don't know how far 20 Canadian Dollars go, in Canada, but you get the same 20 of your currency, to play with, that everyone else gets, in their currency.
I don't know if that helps you out at all, but I just though I would point it out, just in case.