There is no hard and fast rule here. Traditionally you would put down 20% and need about 3% of the purchase price in addition to cover closing costs. So for a $200,000 purchase price you would need about 23% or $46,000. A rather high amount for most people.
However there are many, many kinds of loan programs from 0% to 20% or more. Since 2008, the loan and financial industry has been through several EARTHQUAKE to put it mildly. Since things change so quickly and frequently now, it best to get the advice of a couple of compentent lenders.
There are several down-payment assitence programs that can help low and middle income earners with the down.
Your bargaining position is improved and you will have more choices with the lending industry the better your credit score is , the stronger your employment history is, and the more your personal assets you have.
There are many escrow fees and steps. Most of them have a reason, some of them you get to choose to include or not, and many are negotiable. Ask me for my buyers guide that has more details.