this was my deal - best i could calculate to qualify for both $5 rr and the $10 rebate:

b 2 smart start cereal $5
b 2 special k cereal $5
b 4 poptarts $8
b 2 special k bars $5

total $23 - $5 mfg coupons - $10 rr - $10 kelloggs rebate = $2 cr
you could buy 6 poptarts and shave $1 off the total and increase the credit

any other thoughts for lower combo?
have a few more to do