It's essential to have a knowledgeable agent present when shopping for new construction, and is here to help you navigate through your options in the Pittsburgh area.
Buyers of brand new homes in a development don't like to see houses sold after theirs go for less money. Knowing this, the builder or developer often won't bend on price. (You'll appreciate this behavior after you've bought a home in a development of new construction!) Regardless, depending on the market and the status of the project, there's sometimes room for negotiation.
Consider a property has been on the market a long time and the builder is deeply invested, then you have some room. The same goes for show or model homes that have been sitting for a while. However, if a home was recently completed, don't count on being able to get a deal.
You can always ask for assistance in other ways when purchasing new construction. For example, closing costs are one way for you to save without lowering the price of the house. The same goes for amenities - ask for things an allowance for window treatments, a garage door opener, a fence or landscaping, or an extended home warranty. That can go the other way around, too. If upgrades are already in the contract, try to get the builder to take them out - you might be able to install them later yourself at a savings anyway.
While you should always negotiate a home warranty so problems can be fixed, it's also imperative you get a home inspection before closing. Inevitable problems can be repaired (by the builder) before you move in and larger issues identified before they become your problem. Since an inspection is relatively inexpensive, some new home buyers get an inspection after being in the home for 10 or 11 months - that way, the builder can make the repairs before a 1 year warranty expires.