Do a bit of reasearch. Check the Companies Registration office to see how the business returns have been for the builder, the developer for the past couple fo years. Know as much as you can about who you are dealing with.
You may find that the builder is now only an intermediatiary between you and the bank who own the property. You can find out which bank owns the mortgage on the property through CRO.
Then ask how much they want for the house, how much they'll take and make an offer much lower than that. Depending on the pressure from the banks, their cash situation and a willingness to offload property ( more homes sold the easier it will be for them to clear the last few, more occupancy = more desireability) you could strike a pretty decent deal.