Here's a little-known hack for nabbing holiday deals

Ti_ser | iStock/360 | Getty Images

Feeling confident that you got the best deal on holiday purchases may be a little easier this year—if you start paying attention today.

Why Oct. 30? Several big players in the credit card industryincluding Visa, MasterCard, Discover and Citibankoffer price matching as a perk to cardholders. In most programs, if you spot a lower advertised price within 60 days of purchasing the item with that card, the issuer will refund you the difference.

For purchases from Thursday on, that's a period that covers the gamut of seasonal promotions, including both Black Friday week and a few post-Christmas sales.

Read MoreAre you ready for the holiday sales rush?

"It's a great benefit, because regret's a horrible feeling," said Kevin Yuann, director of credit cards at NerdWallet.com. "No one likes to wake up the next day and realize something they just bought got cheaper."

Using the programs, a smart shopper could knock out their list with the first good deals they see, and file claims later for any better deals that come along—saving themselves time and stretching their holiday budget.

Citibank says under its Price Rewind program, which automatically tracks purchases that cardholders register, 1 in 4 purchases over $100 nabs a price break. The average savings: $85.

Some price-matching programs may even let shoppers enjoy Thanksgiving uninterrupted and sleep in on Black Friday.

Both Discover and Citibank told CNBC.com that their price-matching programs will cover many (but not all) Black Friday sales. A Discover spokeswoman said, "Sales that are advertised as occurring only until a specific time and doorbusters are both eligible for Price Protection."

Read MoreSavings tricks to bulk up your emergency fund

Citibank's stance is new, as a result of a program overhaul earlier this fall that also raised caps on price-match offers and eliminated the minimum price drop to file a claim. "Black Friday ... the day after Christmas, all those sales are now eligible," said Ralph Andretta, head of product management at Citi Cards.

MasterCard and Visa did not respond to requests for comment about how their programs would apply during Black Friday and other holiday sales.

Of course, there's plenty of fine print for shoppers to assess before they rely on cards' price protection to reap holiday savings. "The challenge with it is, a lot of purchases aren't covered," said Yuann. "That would be something you'd want to know," he said.

Read MoreHot toys your kids will want this year

Purchases made on debit cards and corporate cards usually aren't eligible. Issuers exclude certain items (such as jewelry or customized goods), purchase sources (like international retailers and online auctions) and kinds of deals (like goods that come with free bonus items, going-out-of-business sales).

They may also only match prices found at specific online and bricks-and-mortar retailers.

Citibank's program, for example, generally excludes items requiring a service contract, said Andretta. So a Black Friday cellphone doorbuster wouldn't qualify, unless the deal didn't come bundled with a wireless plan.

Cardholders should also pay attention to program caps, especially if there are several big-ticket items on your list. MasterCard's program allows up to four claims per year, and a maximum $250 refund per claim. Discover and Citibank allow unlimited claims but have annual refund caps of $2,500 and $1,200, respectively. Their per-claim refund maximums are $500 and $300, respectively. (Visa did not provide current information.)

Read MoreRising credit card debt may dampen holiday budgets

Most programs require proof of the lower price in the form of a dated advertisement. You'll also need to hang on to your original receipt or register the purchase with the issuer, and submit the price-match claim within a set period of buying the item or spotting the cheaper deal. Discover offers the longest window, giving cardholders up to 90 days after purchase.

The onus is generally on the consumer to find the cheaper price, so be sure to save weekly newspaper circulars and set up price-drop alerts on a site like CamelCamelCamel.com (which tracks Amazon, specifically), TrackIf.com or Cartbound.com.

Even with Citibank's program, which does the searching for you, it can pay to track prices on your own. Terms warn that the program "does not guarantee that it tracks all retailers or that it will find the lowest advertised price." Andretta said consumers can submit their own claim if they find a better price than the bank does.