They have a FREE day on the third Tuesday of the month. FREE parking.
I take my 2 year every month. Parking lot gets full so I usually park in the lot where the buses park. I take my jogging stroller and do my exercise first and then let my son loose to run around and watch the peacocks, squirrels, ducks, fish, and birds.
The place is so big that once inside it doesn't get crowded.