Classified Ad Website

We need a classified website designed. It will be for renters. Landlords would post what they have to offer and potential tenants would be able to search a database for what they have an interest in (such as [login to view URL]). I potential tenant would get contact information to be able to contact the landlord directly which would be listed in the landlords ad. I want the ability to charge for listing but have the option to make it free. I'm not sure what would be the best programing language for this type of project.