Usually the owner has already appointed someone to sell the property on his behalf and that person is called the broker . Though some think that dealing directly to the owner or developer will save them time and money, a broker will still be advantageous to the buyer for the following reasons:

Broker facilitates the whole transaction process 
From setting appointments/meeting, negotiations to furnishing of legal documents and other requirements from the pre-sale to post-sale stage, the buyer and seller is relieved from the hassle and stress of the menial work. Sometimes the seller/owner may not have enough technical knowledge on the legal requirements for the sale of his property, so it is safe and practical to involve a broker in a transaction to have someone in charge of the documents and the processing work.

Broker trips the buyer to the property sites. 
The buyer has the privilege of being tripped by the broker to the sites of the properties for free. The buyer no longer has to worry searching a local city map where the property might be located. It is the responsibility of the broker to lead the buyer and set appointments for the site visit.

Broker acts as negotiator
During negotiations, the broker is an indispensable party as witness and negotiator for both seller and buyer. A third party may be necessary to ensure that all agreements is recorded and is put on paper. If the buyer may find it hard to ask for a lower price to the owner, the broker may negotiate in behalf of the buyer.

Broker can give recommendations of other alternative properties 
An owner may try to convince the buyer that his/her property is a good choice, but the broker is a good source of recommendations of other alternative properties to the buyer. Usually a broker keeps an “inventory” of properties that he/she is allowed to sell. Through this, the broker gives the buyer a wider range of choices and saves his time and effort. Instead of looking for 20 owners of properties, the buyer has to find only one broker that has a listing of 20 properties.

Broker can search for more properties in behalf of the buyer 
If still the buyer can’t find the property that fits his specification, and it isn’t found on the broker’s inventory, the broker will exert further effort to search other properties. The broker may use his network of friends in real estate to quickly get more property listings that might fit the buyer’s specification.

The same is true with development projects (e.g. subdivisions, villages, condominium units, etc) A developer will appoint brokers as marketing arms to sell the units in the project. But take note that whether you go direct to the developer or course the transaction through a broker, most of the time you still get the same contract price. So why not go with the benefits of dealing with a broker.