It's not a requirement, but it's also in your best interest to have a real estate agent. Buying real estate can be complex and is not as simple as just signing a contract. It shouldn't cost you a thing to work with a buyer's agent, either. An agent will do research to make sure you're getting a good deal and will know to look for things like defects in the home.
DISCLAIMER: Brandy A. Peeples is licensed to practice law in the State of Maryland. This answer is being provided for informational purposes only and the laws of your jurisdiction may differ. This answer based on general legal principles and is not intended for the purpose of providing specific legal advice or opinions. Under no circumstances does this answer constitute the establishment of an attorney-client relationship. For legal advice relating to your specific situation, I strongly urge you to consult with an attorney in your area. NO COMMUNICATIONS WITH ME ARE TO BE CONSTRUED AS ARISING FROM AN ATTORNEY-CLIENT RELATIONSHIP AND NO ATTORNEY-CLIENT RELATIONSHIP WILL BE ESTABLISHED WITH ME UNLESS I HAVE EXPRESSLY AGREED TO UNDERTAKE YOUR REPRESENTATION, WHICH INCLUDES THE EXECUTION OF A WRITTEN AGREEMENT OF RETAINER.
Realtor not needed. ATTORNEY NEEDED.
I may be guessing or not licensed in your state. No atty/client relationship exists. I earn my living collecting points for "helpful" answers.
You do not need to get another real estate agent involved. Get a real estate attorney to review your purchase and sale agreement BEFORE you sign it and put any earnest money down.
This is not legal advice.
Unless you can get the seller and listing agent to reduce the purchase price (because they would not have to pay commission to your agent and the agent's broker), it does not cost you any money to have an agent working for you (because your agent would be paid by the seller).
Your agent would be working for you. An obvious service provided by your agent would be to show you properties. However, if you do not want to look at other properties, the agent can still be useful to you by presenting your offers and counteroffers, provide you with advice about real estate purchases, introduce you to other professionals (such as inspectors and mortgage brokers).
There is no law in WA that would require you to hire a real estate agent or an attorney to help you with your real estate purchase. On another hand, unless you can do everything that professionals would do for you, you likely should hire professionals to make sure you are doing everything you should be doing to protect yourself.