The Edmonton Expo centre is operated by Precise Park Link.
The location hosts numerous events every month and there is usually an option to pay in advance.
However, once you pay you cannot adjust your license plate on your own. You can by request through HONK support, however, its generally advised to not pre-pay until you are certain on which vehicle you are driving.
There is ample parking onsite, and prepaying does not guarantee you a prime spot or give you special privileges.