A down payment is the amount of money you spend upfront to purchase a home and is typically combined with a mortgage to fulfill the total purchase price of a home.In addition to your down payment amount, your credit score, credit history, total debt and annual income will influence how much house you can qualify for.A great tool to see how much you can afford based upon your down payment and annual income is Zillow’s affordability calculator.n addition to your down payment amount, your credit score, credit history, total debt and annual income will influence how much house you can qualify for. A great tool to see how much you can afford based upon your down payment and annual income is Zillow’s affordability calculator.