When I started using coupons, I was discouraged that I couldn't use a coupon for every item bought. Then I realized that some items were actually less w/o a coupon which led me to a secret of true savings.
I still shop sales and try to attach coupons when I can but instead of counting money saved, I divide total items purchased, found at the bottom of the receipt, into total $ spent. This gives me $/item. I am giddy when I spend only $1.50 for laundry soap, meat, beauty care, etc!