The houses generate more money depending on their upgrade. Cottage costs $300,000 Suburban house costs $1,000,000 Mansion costs $1,500,000 Every ten seconds you get a payday
Lvl 1 house: plot (Brown) Lvl 2 house: cottage (Small one chimney) Lvl 3 house: suburban house (small two chimney) Lvl 4 house: mansion (big two chimney)