So today on the way to work I passed by the Esplanade and I saw that parking garage I was talking about earlier. It's Scott ST/The Esplanade. It said from 6PM-6AM parking is $6, though it said "rates may change on event days". Not sure if that includes Leaf games, but it seems like a pretty good spot. If you wanna chill and drink some beers after the game there's a bunch of pubs on the Esplanade too which is nice.
Yeah I bet those events mean Leaf games or popular concerts.