ContestWP has the ability to automatically select winners for every specific number of entries. This allows for contests to have instant winners without having to specify codes that have a prize associated with them. There are two parts to setting this functionality up. The first is to enter generic prizes. Generic prizes will be used to randomly select the prize the instant winner will get.
Once the generic prizes are entered we need to enable the functionality. Go to the contest’s settings page and look for the option “Instant winner ever X entries”

Specify a number greater than zero and then save the settings. As an example, if the number that was specified is “5” then every fifth submission will be selected as a winner. Now every time a contestant submits a valid code they will have a chance to win. This will keep working until all of the generic prizes have been given away.