As Sharon said, a contractor can give you an estimate. Price can't be judged just by square footage. What also must be considered is what's in the home and on the outside of the home. For example, are appliances and heating system still inside? What is the siding, is it asbestos shingle? And who will be handling the permitting.
Make a few calls, demo contractors can get you estimates within a few days.
Keller Williams Atlantic Shore