Why do I need a Realtor?
You should absolutely have a Realtor on your side when buying a home. The Realtor who is selling the house represents the seller's interests.A buyer's agent will represent your interests instead of those of the seller and it doesn't cost you anything. 
Navigating a real estate purchase is tricky business. A negotiator who knows the market can save you time, money and heartache by helping you make the right offer—playing hardball when necessary—and staying on top of the process.
Your Realtor agent can help you :
Provide comparable sales from the tax rolls.
Provide sales data from MLS based on map searches.
Pull property profiles reflecting sales history, property data, demographics and neighborhood services.
Obtain a copy of the home's historical documents.
Run reports on listing agent's list-price to sales-price ratios.
Calculate annual facts and trends about an area.
Suggest pricing strategy.
Prepare a strong offer that presents the buyer in the best light based on market demands and agent interaction / networking.
Review of documents for loopholes and obtain disclosures.
Provide a buffer between you and the seller's agent.
If you feel competent that you can handle a sale or purchase on your own, you probably can. But you may always wonder if you paid too much.