"Consumers today can really save a lot of money if they invest an hour of time before they shop," Mr. Borrell says. "That hour is best spent sorting through their mail or going online searching for deals. If their time is worth $25 an hour at work, it's worth maybe $50 an hour for shopping." Some online coupon websites are coupons.com, coolsavings.com, and smartsource.com. Groupon.com offers a twist: one big local discount a day.