Is there a cost for submitting an application to the AppStore?
So long as your USD99 annual membership fee for Mac Developer Program is current (and you don't break the Agreement or any NDA), that paid membership already covers the following typical software distribution costs:


set up your App ID for distributing your app
set up and download credentials needed to sign the app for distribution via the App Store.
keeping your tax information and deducting the appropriate withholding on apps sold for selected countries' App Store.
review of your app
hosting of your app (at App Store)


etc.