If you live in a rural area and can't get mortgage lenders to give you the time of day, try the Rural Housing Service. It exists to help farmers, ranchers, and rural residents find affordable housing with low interest rates and low down payments. They're online at http://www.rurdev.usda.gov/rhs/index.html.
The more money you give your mortgage lender as a down payment, the lower your interest rate on your loan will be. Twenty percent is standard with some loans, though others require less than 5 percent, along with private mortgage insurance in case of default.