This will vary depending upon the area and the agent you select. Some agents will accept a flat fee depending upon the amount of assistance you will need. But if the home is listed with an agent, their listing agreement will cover paying the buyer's agent from the commission earned from the sale. If the home is a for sale by owner, a buyer's agent can ask them to pay the commission, or flat fee, from their proceeds. It really will depend on the property you find, the agent you hire, and the location you are in.