Cerial: $3.14 for 11.2oz;
Cookies: $5.04 for 18 cookies;
Eggs: $2.04 for half dozen;
Grapes: $9 for 5lbs;
Orange juice: $2.08 for 16oz;
Watermelon: $3.72 for 4lbs.
The way to solve for these or to check is by dividing the price by the amount. For Cookies, $5.04 is best because [ 5.04 / 18 = $0.28/cookie ] and not $4.50 because [ 4.50 / 15 = $0.30 / cookie. ]. Hopefully this helps!