"The index tends to run in a range," he explained. "In September, October, November in 2007, it popped out of its range for the first time… And, for the first time since then, we are seeing a tripping out of the range," said Boal, a former Wall Street executive.
Boal considers coupons a leading indicator because you don't need months of data to see consumer behavior patterns emerge. He said he expects the payroll tax hikes, rising food and gas prices are squeezing household budgets.
(Read more: Strike Three! The American Consumer Is Out)
It also helps to look at the types of coupons shoppers are redeeming. The most popular ones right now are for soup, cheese, rice, pasta and M&Ms.
"When people are feeling tightened, they seek comfort food. But, also things that make them feel better from personal care and beauty. Dove soap, Pantene and Vidal Sassoon are trending right now," said Boal.
Since the last recession, consumers have really changed their buying patterns, according to Boal. But the behavior Coupons.com is seeing now represents another shift. Those who weren't affected by the last recession are now tightening the reins.