The only free option in WordPress that actually works and allows you to create paid listings. You can set it so that people can buy 1 listing or a pack of 10 or whatever number of listings and charge for that. (Needs Woocommerce, also free, set up to use the paid listings function).

The only small complaints I have are:

Clicking on the “add listing” button takes you directly to a form to fill out for the listing. If you are logged out, it asks you to log in, if you are logged in and haven’t paid, it present you with the listing form, and only after you try to submit, does it asks you to pay. Not a good experience for customers to find out after they finished filling it out that they have to pay. Would prefer a dedicated page where you can add a listing and first, it shows you the packages that you need to purchase (eg free, 1 listing, 10 listings), pay, and then fill out the form.