Sometimes you can get lucky and park for FREE along Oak Street or McGee and enter Sprint Center at the Oak St entrance.
Some people are unaware the meters DO NOT need to be fed after 6 pm and the Oak St side is much faster to get in the building.
Downtown KC parking is always a pain in the rear. Parking usually costs $10-$20 and if you go for the "most convenient" very close to Power and Light, the Sprint Center and everything else it usually turns out the least convenient.
As soon as the event at the sprint center gets out, the thousands of people who parked in there are in a giant line and you can set there for 30 minutes to an hour... The best place, in my opinion is in the Cosentino's parking garage. A little farther to walk, but going to be one of the first out!
If you are going to the Sprint Center, another secret is go out for a "bite to eat" first, then when the parking attendant asks where you are going, you can honestly say "out to eat" and get the non-event cheaper rate!