I assume that one can subscribe to Sportsnet World for the day and then cancel before 10pm (if you use Rogers cable for example), so that it's pro-rated at roughly only 75 cents for the day. If a race goes past 10pm, cancelling the next day would just add another 75 cents to the tab (assuming that the channel is $20 a month).
I think Hollywood Suite forces subscribers to pay for the full month (regardless of when you call to cancel), so early cancellations wouldn't save any money for that, but perhaps Sportsnet World does allow the pro-rated cancellation trick, just like it works for Sportsnet 1 (via Rogers, anyway).
Warning: I'm not playing with a full deck.