I have luck finding them in the entrance and near customer service. Also if there is a 4-way display in a main aisle, coupon booklets might be displayed on those as well.
Have you tried emailing companies and asking for coupons? I have been getting a great response in the form of coupons. Lots of high amount or free items. If you haven't already, you might want to consider joining Procter and Gamble's
www.homemadesimple.com. They send out a book of coupons periodically. The last one had over $31 in savings for all types of cleaning items.
One other thought, keep an eye out for the store's magazines. Our Publix prints all types of magazines for families, going green, organic, and entertaining. Each issue usually has manufaturers coupons in it that can be used in any store.
Good Luck and keep us posted on what you find.
Save BIG!!!