I have the free plan with under 300 saved submissions but it says I'm out of storage.

Is there something I'm missing? I have the free plan with under 300 saved submissions but it says storage is full and telling me to upgrade.

There are several forms in the trash for your account that have submissions.  Those submission still count towards the total.  Remove those forms from the trash and they will no longer count towards the total.  Here is how to restore them:

https://www.jotform.com/help/134-How-to-Restore-Deleted-Forms

Instead of restoring them, purge them from the trash to fully remove them.