Also keep in mind that if you are using Park&Fly often you should get a membership in their Park&Fly rewards program. 1 point for every dollar you spend. 65 points earn a free day in the A parking and 375 points a full week. Depending of how much you pay, that represent roughly 1 free day per 5-6 days of paid parking. So if you already manage to get a 20-25% discount that represent another 15% extra value.

http://www.parknfly.ca/Cusloyalty/en/JoinProgram.aspx