Builders do not often negotiate with anyone, they do often throw in extras or upgrades, but they like to hold firm on prices if they plan to build more homes in that subdivision. Giving you a deal will mean everyone else buying later will want the same price so they give up other things rather than price discounts. Having your own agent can help protect you. Realtors work under a code of ethics and we have laws to follow. A builder, who is just like any seller, can tell you anything and often will not be held accountable for it later. Let's say you ask for stained trim in the house, builder says, "sure I will do that for you" then on closing day there is none and you realize it was never written in the contract so the builder is off the hook for it even though they said they would add it. An experienced Realtor knows that trick as well as many others builder play. Use an agent to protect yourself and do some of the legwork needed.