(a) General rule.— The parties if they so intend can conclude a contract for sale even though the price is not settled. In such a case the price is a reasonable price at the time for delivery if:
- (1) nothing is said as to price;
- (2) the price is left to be agreed by the parties and they fail to agree; or
- (3) the price is to be fixed in terms of some agreed market or other standard as set or recorded by a third person or agency and it is not so set or recorded.