The amount you will need depends on the type of loan you choose. A typical 20 percent down payment on a $300,000 purchase would be $60,000. The National Association of Realtors estimates the median down payment percentage in America to be 14 percent, and that would be $42,000. If you qualify, you might need to put down as little as 3 percent for a conventional loan — that would come to just $9,000, but would require monthly PMI payments.