Hi
Thank you for your reply. Yes, I am planning to create a custom checkbox as explained here in your documentation : https://wpadverts.com/documentation/custom-fields/
User will mark this check box if the item is sold already, accordingly WP adverts changes the value in price to “Sold”.. This is what i am thinking.
And yeah, my second question have been solved (added to function.php). Thanks. Your support is awesome.