Many real estate agencies (including Zillow) use paid advertisements for property management companies, mortgage lenders, and other businesses interested in real estate mobile app audiences as a prime source of their income. In addition, Zillow, for instance, makes money on premium services for agents. However, your efficient monetization model can vary depending on your business specifics and user preferences. Consider trying the freemium monetization model. It works by giving users access to basic features for free and charging for premium content.