If you've ever bought a house or thought about it, one of the things you almost always consider is a choice of agent. You want to make sure that that person helps you look for the right place, because they know more about the market and where to find the right houses. However, the person who owns the house you want to buy also has an agent. Even more strangely, sometimes that person is one and the same. What gives?
Keep in mind that there are two types of agents in a transaction like this: buyer's agents and seller's agents. Typically, one agent will not represent both parties, although the agent can if the parties agree to it. Most of the time, each party will have an agent who represents their own interests. Be sure, especially if you're a buyer, that you sign something saying that this agent is representing you; if you are dealing with the listing agent for a property, they are going to operate on the assumption that they are representing both parties.
Realtors are paid almost exclusively by commission, and that commission comes out of the selling price of the home. The buyer should not have to worry about paying their agent, as the buyer's agent's cut comes out of the commission.