(KPIX 5) — When you hear or see something is on sale, you probably assume it’s a limited-time deal. But it may be anything but that.

It’s something retailers know, and according to a new study, something many cash in on.

READ MORE: SF Citizen Detective Finds Her Missing License Plate on Identical Car Stolen From Another Resident

Advocacy group Consumer Checkbook tracked sale prices at 19 national retail chains and found over 10 months the sale prices rarely changed.

Six stores: JCPenney, Kmart, Kohl’s, Macy’s, Neiman Marcus and Sears kept certain items on sale more than 75 percent of the time.

For example, a Keurig coffee maker at Macy’s was on sale nine out of the 10 months. A Craftsman tool kit at Sears was on so-called sale for 10 months straight.

Consumer groups point out if the regular price was never the real price, then the item was never actually on sale.

READ MORE: San Mateo Police Officer Spots Stolen Vehicle; Driver Arrested, Cited, Released

“It’s highly deceptive, to be sure,” said consumer advocate Joe Ridout. “Stores are manipulating consumers into overspending or buying things that they might not otherwise buy because they’re planting the seed that this is some special discount.”

Once they get you into the store they know you’ll buy more, said Ridout.

This isn’t a new phenomenon. TJ Maxx, Burlington and Nordstrom Rack have all faced lawsuits for dishonest comparison pricing, while Kohl’s was accused of marking prices up, just to mark them down.

But what is new is that two chains are holding what the survey calls “legitimate” sales. At Costco and Bed Bath and Beyond, the sale prices were only in place less than half the time.

MORE NEWS: San Pablo Eyes New Eviction Protections as COVID Cases Surge

We reached out to all six of the retailers accused of holding sales that take place nearly year-round. Only JCPenney got back to us.  It said it uses a “promotional pricing model employed often in the retail industry.”