Scoring amazing deals on everyday products has become a craze of the post-recession era. But as with anything that smacks of "free money," the incentive is strong to abuse the system.

Coupons are front and center, placed there not only by the dark days of a down economy but also the bright lights of a national TV show, TLC's "Extreme Couponing." The show features over-the-top shoppers who clear shelves of supermarket products and use coupons to pay next to nothing.

Some of the featured shoppers on "Extreme Couponing" have been criticized for questionable tactics, including the use of counterfeit coupons. TLC representatives have repeatedly said it's up to show participants to follow coupon rules and store policies. The Internet, too, is rife with websites advising consumers on how to game the system, even if it's unethical or illegal.

Counterfeiting has become a big problem. The number of counterfeits reported by Coupon Information Corp., which represents manufacturers that issue coupons, went from 18 in 2007 to 486 last year and are on a pace to total 1,200 this year, said Bud Miller, executive director of Coupon Information Corp. The data represent the number of original coupons — for example, "Save $7 on Meow Mix dry cat food" — that have been duplicated over and over again.

"We have a lot more than we ever anticipated," Miller said.

Avid-but-legitimate couponers are upset, fearing abusive couponing tactics will hurt all shoppers as manufacturers and supermarkets compensate for financial losses.

"It's going to accelerate the thing that irritates us all, the constant creeping up of prices and the constant shrinking of package sizes," said Josh Elledge, chief executive "angel" at coupon-deal site SavingsAngel.com.

Part of the thrill of couponing is getting items inexpensively or free. But that can create overzealous shoppers who develop an us-against-them mentality and rationalize counterfeiting and other fraud, experts say.

"That's not sticking it to the man. That's sticking it to everybody," Elledge said.

Couponing instructor Jill Cataldo, who blogs at JillCataldo.com, is among the coupon experts at the forefront of advocating ethical couponing. She said she knows the type.

"They want to get all that they can as cheap as they can, and they don't care who it hurts in the process," she said. "Eventually it trickles down into higher prices for everybody, and that's something you should care about."

Here are tips on couponing right.

Rules. Know them. They're made by the manufacturer that issues the coupon, mostly explained in fine print on the coupon, and by the supermarket that chooses to accept the coupon.

Buying coupons. Coupon experts advise consumers not to buy coupons online or from a clipping service.

Free. If you have a coupon from a dubious source, and it has an unusually high value or specifies getting an item free, it's probably counterfeit.

Decoding. Buy the specified size, version, variety and flavor specified on the coupon. "Many shoppers think that if a coupon 'works' or if a cashier takes it, then it's a legitimate use of the coupon," Nelson said. "Coupon fraud is using a coupon incorrectly, regardless of whether or not the cashier takes it."

Greed. Shelf-clearing is generally frowned upon as an etiquette violation among avid couponers. The intention should be to save money on products you can use, not buy as many as you can.

Fairies. It's good form to be a coupon fairy. If you have a coupon that will expire soon and you can't use it, leave it on the shelf near the product.

Resales. It is generally considered poor form to resell free or cheap items you acquired with coupons.

Donate. If you see a good deal, go ahead and buy several. Donate excess to charity.

Nelson said avid couponers should take a big-picture view.

"These companies never intended for a single shopper to have hundreds of coupons for one item," Nelson said.

"Buying coupons online to be able to do that may not be coupon fraud, but it's not a practice that companies will be able to support long term. They'll need to make coupon policies stricter and change coupon values if that kind of shopping really caught on.

"And that hurts the average shopper."