How much does it cost to part at the center

I typically park a block away on a street that's free. Seems to work well.

What about a graduation on june2nd 2018

Park at the bus station in a $5/day lot. It's only about 2 blocks away. There is no free parking before 6. After 6 & on weekends most meters on street are free.

the garage was 15 fire 6 hour when I went last weekend. the lot was 10 for 6

For the convention center multi story garage it's like 5 dollars an hour, 6 if there's an event. 61 minutes is two hours, FYI.

I parked in a car park a block away for $10.

Was at Auto show for about 5 hours and was charged a whopping 18 bucks

It depends on if you are going to an event or not and how close you want to park. It's always best to check around a few days before. Be aware though, some parking lots will charge higher for event days and may not advertise it on their signs.