Some domain name registrars offer this. Feedback is that it suffers from some downtime, but this is not to say it is better or worse than other free service. Fewer providers offer free website hosting for your own domain name. These sites allow you to list your domain names for sale. SEDO.de - SEDO, the Search Engine for Domain Offers, provides a worldwide database of used domains.
Commission is charged on sales.
If you have set up a website to promote your domain names for sale, then these sites provide facilities to promote your site. Free inclusion of your site in the ring. Reciprocal link required. The author is not making any recommendations about the sites listed here, but is simply providing the information that they are advertising these services.