Earnest money is a deposit a buyer submits after an offer is accepted to demonstrate they are serious about completing the purchase. It is typically held in escrow by a neutral third party and later credited toward the buyer's down payment or closing costs.
The amount varies by market and price point but often runs from one to three percent of the purchase price, and in highly competitive markets it can be higher. A larger deposit can make an offer more attractive to a seller.
If the buyer backs out for a reason covered by a contingency in the contract, they usually get the earnest money back. If they walk away without a valid contractual reason, they may forfeit it to the seller.