While drivers will be paying $10 to park and bus riders will be paying$3 bicyclists can park on the Horticultural Center grounds for free. Google Maps Bicycling Directions estimates that the trip by bicycle from Center City is 30 minutes or less. Probably competitive with the bus ride from Broad and Sansom if you add in the wait.
Best of all is that you will get to see hundreds of Cherry Trees in bloom en route to the festival.
Admission to Sakura Sunday is a $5 minimum donation.