With ads changing every seven days, grocery prices ping pong. It's a mystery to most -- but not Kati Kiefer.
She's the brains behind TrueCouponing.com, where she records food prices every single week, and analyzes changes over time.
Kati's discovered a supermarket secret: the "sales cycle." She's found a predictable 12-week pattern in grocery store sales. She says on everything from dinner to detergent, prices dip at least once every 12 weeks.
"So, no matter what laundry detergent you use, if will come on sale, with patience over 12 weeks," she says.
The most proficient penny pinchers pair coupons with sales. But this week's sales and this week's coupons don't always match up. That's why Kati keeps her old coupons on file.
"A lot of coupons don't expire next week," she noted.
Kati stockpiles coupons to double dip, clipping those coupons only when the 12-week price cycle spins in her favor. When prices are down, she stocks up.
"If you buy enough to last 12 weeks, you'll never have to pay full price again," she says.