Look at the foreclosures in your area. It is likely a lot of them would be new or near new.
Price out a lot, foundation, electricity install, well, septic, and then a house. (Modular for quick easy answer)
Ask a modular home dealer (no, not trailer or double wide) for what it would cost to put this style of house (you want) on a lot in this area (you want to be in). They do the hard work for you and then you can run the numbers yourself.
Which is cheaper? The foreclosure (or short sale) is likely to come in under the price of new. But only looking in your area and being sure will tell. If you have some shiny new subdivisions in your are that are all foreclosing you would likely get a great deal there. Yes, even compared to new. But if you are looking at very old houses you can have repair problems. If the house is almost new be very concerned about it having chinese drywall as it is destroying electrical wiring and a lot more. It is cheaper not to buy a house that has chinese drywall in it period.