I am sorry to say that we made a mistake in the price of the product because we mistaken its number.The price was $2.00 in last contract; however,we offered it to you at a price $1.80 in the contract made in yesterday.Now we would like to inform you that the price is $2.20,and the explanation stems from the fact that the prices of materials has been raised much more than before.In attachment please find the new sales contract. I am sorry to say that we made a mistake in the price of the product because we mistaken its number.The price was $2.00 in last contract; however,we offered it to you at a price $1.80 in the contract made in yesterday.Now we would like to inform you that the price is $2.20,and the explanation stems from the fact that the prices of materials has been raised much more than before.In attachment please find the new sales contract.