Is the submission 100 or 500 per month for the free version?

Is the submission 100 or 500 per month for the free version? Can I delete submissions as to not go over the limit which ever it is?

For the free account, the monthly submission limit is 100 and the total submission storage per account is 500. 

For the 500 total submissions storage, it means that free users are limited to a total of 500 submissions in their account. For every submission exceeding the 500 will cause for the oldest submission in the account to be removed. To clear the submission storage, you need to delete the old submission. To do that, please follow this guide: https://www.jotform.com/help/377-How-to-Delete-Form-Submission-Data. Keep in mind that deleted submissions are not recoverable.

If you reach the monthly limits, your forms will be disabled. The monthly limit resets back to 0 every first day of the month.

For more information regarding on Account Usage and Limits, please visit this link: https://www.jotform.com/help/408-Understanding-Your-Account-Usage-and-Limits

I hope that helps.