You can offer anything you like, but it's a good idea to get information from an expert on how much similar homes have been selling for in the area before making your offer. Ask your agent for details of recent sales, and make sure that agent is representing you as the buyer, not the builder as the seller. Study closely what they give you, each home is different and various features will add and subtract when compared to the one you are looking at, then take view on what you think is fair market value TODAY. What he was asking for it 2 years ago is not relevant to today, neither that it has been on so long. There are plenty of gorgeous homes out there that are very reasonably priced, but not selling for almost inexplicable reasons. I'm sure the builder will be delighted to receive your offer, even if it's not accepted, but make it through a Buyer's Agent, who will help you work out the right price to offer, which is going to save you money in the long run.