PHILADELPHIA (CBS) — The retail wars for your Christmas dollar are already heating up. Many big retailers are promoting that they’ve got the lowest prices, and if you find an item elsewhere for less, they’ll match the price.

But as 3-On Your Side consumer reporter Jim Donovan tells us, be sure to read the fine print.

That’s right because while some stores will give you difference in cash back, and others in the form of a gift card.

Doing the match itself may not be as easy as you might think.

Wal-Mart, Home Depot, Best Buy, Staples, Nordstrom and Target. They’re just some of the big retailers that are willing to match a competitor’s prices.

The rules are basically the same for all of them. The item has to be the same, size, brand, and model number.

Sounds easy. But not always according to Brad Wilson who operates a shopping comparison website.

Take electronics for instance, retailers like Wal-Mart will advertise a TV that looks like the same TV you see a Target, Best Buy or another store, but here’s the catch.

“They actually get an exclusive model number for the just for their store. So on the front end you can’t do a price comparison, even though in reality it’s identical,” said Wilson.

And since the policies say the model numbers have to be the same, consumers don’t get the matching price.

“it’s a big hole in the integrity of the price match process,” said Wilson.

In addition, many price matching policies exclude Black Friday sales and most won’t match internet sales. And as shopper Gloria Pittman points out, there are a few other exclusions in the fine print.

“Some stores have no rain checks, limited quantities, and so when they run out of the quantity that they have they won’t match the price,” said Pittman.

Reported by Jim Donovan, CBS 3