U.S. citizens are exempt from a reciprocity fee for stays up to 90 days until June 22, 2016, or until an Executive Order is issued to permanently revoke the fee.
Typically, U.S. citizens, Canadian and Australian nationals are visa-exempt for stays up to 90 days, including business visits, but they must pay a reciprocity fee upon arrival. The reciprocity fee for U.S. citizens was USD 160. Australian and Canadian nationals must still pay the reciprocity fee.