I once was a coupon queen, but nobody doubles here anymore and we started eating a keto diet so those days are over. It was a rush though. One time I had over $100 worth of stuff in my cart and ended up paying a couple of bucks. You were supposed to get a free turkey if you spent more than $75. The cashier balked but the guy behind me said she earned it to give it to her. It turns out he was the store director and loved couponers. He started giving me the ads in advance and would special order for me. Unfortunately, he moved away and they quit double couponing.
My other awesome success was at Kmart. The company that makes Halls cough drops had pads of coupons everywhere to get $5 off any 3 items. Kmart had the cough drops for .99 each, so there was $1.xx in cash back each time. They also had self-checkout. So my son and I would go in and buy 3 packs and get $1.xx back. Rinse and repeat. We repeated this over and over at every Kmart. My son got tired of repeating this so he got a huge stack of coupons and bought a PS2 console in one transaction. The cashier and manager weren't happy but it was legit. Shortly after that, they shut down the self-checkouts. We probably made about 400 - 500 overall including the PS2. We had a garage sale and sold them for .50 a pack or 3 for $1. We sold a bunch but still had tons left. We kept family and friends well supplied with cough drops for years!