And then there are closing costs. Those two costs will equal the total cash needed to close. Closing costs are roughly 2-2.25% of the purchase price. So if you’re looking at a home for $500,000, plan on closing costs to be around $10,000.How much down payment is needed will vary, depending on the loan program.Down Payment Requirements for Loans.How much cash you will need to purchase a house is dependent on the loan program, purchase price range and certainly your market area.1  Conventional financing – Needs a minimum down payment of 5% (varies on maximum loan size in your area).ow much cash you will need to purchase a house is dependent on the loan program, purchase price range and certainly your market area. 1  Conventional financing – Needs a minimum down payment of 5% (varies on maximum loan size in your area).