Answer:
amazon
Explanation:
let's find the price per pack to solve
best buy:
7 packs = 28 dollars
divide both sides by 7 to get 1 pack = something
1 pack = 4 dollars
amazon:
12 packs = 38 dollars
divide both sides by 12 to get 1 pack = something
1 pack = 38/12 dollars = 3.16666666667 dollars which is less than 4 dollars, so amazon is cheaper in terms of price per pack