I have saved lots of money using coupons, but they are not to be used randomly. There used to be lots of rebates, too, but not so much anymore.
Here's how it works:
Get some #10 envelopes and label them with various categories as follows: Soap and bath products, shampoo and hair care, pet food, baby items, detergent, canned goods, frozen foods, etc. You get the picture.
Make a list on a spreadsheed or word processing table with these headings: (1) Brand name, (2) savings amount, (3) expiration date.
File the coupons in a tackle box. (Take the tackle box with you when you shop.) Once a month, sort your computerized list by expiration date and discard any expired coupons.
Wait for the item to go on sale. Look on your computerized list to see if you have a coupon for the item. Supermarkets are good about putting coupon items on sale. Use the coupon only after the item is on sale.
Some stores offer double value on coupons. But sometimes those same stores have higher prices, so be careful.
Once I went shopping on double coupon day and bought about $20 worth of goods. After deducting the coupon savings, I owed one cent. The person in line behind me stepped up and said, "Here, I'll get that."
Look for rebates, too. These are not as common as they used to be.
My ex-husband was an unbeliever, but he finally told me, after a year or so, that we actually had a better quality of life because of my system.