THIS week 4 packages of Oreos will cost Sally $10. This is because 2 packages cost $5 dollars, but Sally is buying twice the amount of packages(which means the price will also be twice the amount it is). NEXT week, the 4 packages will cost sally $13.16. This is because, without the sale one package of oreos cost $3.29. The price will be multiplied by 4 because sally is buy 4 packages. To find how much money Sally is saving on Oreos by buying them during the sale, just subtract the cost of the cookies during the sale from the cost of the cookies regularly. ($13.16 - $10 = $3.16) Sally is saving $3.16 dollars