I started a new list of all the "store" coupons I've been getting either by the mail, e-mail or from surveys. On the list I list the store, the discount and expiration date. I cross off once I use a coupon. That way when I trot to that store I can check the list to see if I have a coupon. A lot of times I don't use these coupons, so I don't carry them around with me. But there are times I shop at a store and come home to find a 15 percent off coupon in my pile. A side note, if you do find a coupon after you make a purchase, just go back to the store and customer service will adjust the cost. Sometimes, you can even do this over the phone.
Hopefully, my new system will eliminate multiple trips.