You can start an online house for sale by owner website … Targeting your local city Or country.

Your aim will be to rent out advertising & listings space to various home owners looking to sell their houses privately … You can also add an alternative option which charges them to advertise in your print classifieds.

Categorizing the website into various sections will really help customers in navigating your website easily. … Arrange it by; city, land for sale, condos for sale, apartments for sale & houses for sale …

Once you have organized the website … Now add a section for services .. This part of the website will feature moving companies, real estate agents, home improvement & designing companies … And Lawyer contacts. ..etc.

MARKETING:
* You can market your website by getting listed in the yellowpages.
* Direct Mailing & handing out of fliers in urban areas.
* Door to door marketing where there are home for sale signs.
* Advertise to moving companies, reals estate companies, Lawyers and home improvement companies.
* Elevator & billboard advertising can also work wonders … Gives more exposure.
* Radio & Tv advertising .. if you have extra cash to expand.
* Make print classifieds .. To reach more people … it will also encourages more people to try to advertise.

MAKING MONEY:
* Make most of your money by charging people a monthly listing fee OR whatever you feel will work.
* Also add contextual ads to boost your revenues while you start out. .. Google adsense OR Yahoo ad links
* Adding affiliate marketing might help .. If you find the right company to market.
* Since you will be adding print classifieds .. This can be your strength .. because more people will know your brand and try to advertise on your classifieds. .. This equals to more money for your company.

Thats all I can think of … Hope this helped … Have a wonderful day … Check back often, I update daily with new business ideas.