Had a not-so-great experience when I first tried to "do the deals" at Walgreens (the $20 in Register Rewards didn't print out; had to send in a form to have them mailed to me). I just received my gift card from the Free After Rebate items from a few months ago, and my $20 in Register Rewards actually showed up, so I thought I'd give it one more try.
See here for Money Saving Mom's explanation of how to work Walgreens.
The cereal was on sale 3/$7, with $2 RRs printing out (they didn't actually print out, but a manger intervened and put the two bucks on my gift card). I had a manufacturer coupon for $1/2 boxes, so the total cost for the cereal was $1.33 per box.
The rest of the items were free after rebate, so my net cost for everything shown is just the $4!