There are mortgage options now available that only require a down payment of 5% or less of the purchase price. Mortgages with less than a 20% down payment generally require a private mortgage insurance (PMI) policy to secure the loan.
For example, if you pay 10% down on a $100,000 loan, PMI might cost you about $40/month or $480/year. However, the actual rate is based on various factors including the size of the loan, the amount of the down payment, and your individual lending institution. The only way to find out the exact amount is to contact your lender directly.