The simulation elements of House Flip can sometimes be a little too realistic, especially when it comes to budgets!
If you find yourself in a neighborhood or city where the real estate prices exceed what you can afford, you've got to budget your other projects within your CAPITAL means. Building CAPITAL is one of the main objectives in House Flip! You could visit past neighborhoods and cities where there are projects that fit your budget, do some quick flips there, and accumulate enough capital to tackle the more expensive flips in further cities! You'll find that the timers are still short in WACO and KANSAS CITY, thus allowing you to knock out House Flips with little time.
To go back to a past neighborhood, simply tap on the WORLD MAP button from the city map screen, and tap on the city you wish to revisit.
Don't forget the rule of thumb to leave about 20% of your budget for renovations and staging so that you can maximize your profits. For example, if you currently have 100,000 in CAPITAL, you should be looking at projects around 80,000 in CAPITAL so that you have 20,000 left to do your renos!
Good luck!