If you have allowed for featured ad posting, then the featured ad check box appears in the ad listing form at the bottom of the page just above the "Continue" button
They then proceed to the confirmation page which calculates the total ad listing price before going to the payment gateway process.
As of
ClassiPress v3.2, relisting with the option to upgrade to a featured ad was implemented, however there is no option to upgrade an ad that is still running.
Customers can renew an ad when it expires if you allow ad relisting in the ClassiPress admin. They will be sent an email asking if they want to renew.
Featured ads appear in the featured ads slider, but not other aspects of the ad itself such as order or colour. There are some
AppThemes marketplace child themes for ClassiPress which have special functions for featured ads built into them such as a tag or ribbon to make it more obvious.
It's up to you what you want the ad to do when it expires, there is a setting for this in the ClassiPress admin dashboard which allows you to prune the ads or leave them there.
There isn't any advertising management functionality built into the theme to collect payment for banner ads. You can find ad space plugins in the AppThemes marketplace if you want to implement more banner ad spaces. Thanks.