Back in the day real estate was purchased with a requirement of a 20% down payment.

During the last real estate heyday - 2005-2008, there were loans that were granted where a borrower could borrow with a loan for 80% of the purchase price and another loan for the remaining 20%(as your downpayment).

They had different variations of this - there was a 80 - 10 - 10 and a 80 - 10 - 5- 5.  Etc...  All to provide the borrower the necessary 20% down to buy a home.

Today the number(down payment) needed to purchase real estate is much lower.  You can obtain, if you qualify, a 3% down conventional loan.  You can also get a 3.5% down FHA loan that requires less in the way of needing stellar credit.

You can also borrow within a 5, 10 and 15% down conventional loan type.

However, anything less than 20% down in today's real estate realm is going to have PMI attached to it.

PMI - Property Mortgage Insurance.

It is a fee that protects the lender lending you the money when you have less than 20% skin in the game.

How much the monthly fee is going to be will depend on your credit scores and "qualification" ability.  Make sure you ask your lender and PMI is, or can be, negotiable.  Ask the lender you are dealing with is you can borrow without it or get it at a larger discount.