N.Y. Tax Law § 1425
Notwithstanding any other provisions of law to the contrary, the county of Erie, acting through its local legislative body, is hereby authorized and empowered to adopt and amend local laws imposing in such county a tax on each conveyance of real property or interest therein when the consideration exceeds five hundred dollars, at the rate of two dollars and fifty cents for each five hundred dollars or fractional part thereof; provided, however, that with respect to (A) a conveyance of a one, two or three-family house and an individual residential condominium unit, or interests therein; and (B) conveyances where the consideration is less than five hundred thousand dollars, the consideration for the interest conveyed shall exclude the value of any lien or encumbrance remaining thereon at the time of conveyance. Such local law shall apply to any conveyance occurring on or after June first, nineteen hundred ninety, but shall not apply to conveyances made on or after such date pursuant to binding written contracts entered into prior to such date, provided that the date of execution of such contract is confirmed by independent evidence such as the recording of the contract, payment of a deposit or other facts and circumstances as determined by the treasurer.
N.Y. Tax Law § 1425