Good grief! Nearly 1 million folks have wrapped up their Christmas shopping

Overachievers who have already started – or finished – their holiday shopping may still be able to take advantage of upcoming sales.

An estimated 34 million adults have already begun to tick items off their Christmas shopping list, according to a new survey from CreditCards.com. Of those, 1 million have completely "wrapped" this annual task.

The mid-September survey polled 1,000 adults, with a margin of error of plus or minus 3.8 percentage points.

"It really is pretty amazing that so many people have finished their holiday shopping so quickly," said Matt Schulz, senior industry analyst for CreditCards.com. "Some people wear that as a badge of honor."

While early birds have the advantage of ample time for smart shopping – comparing prices and swooping in on the best deals – there's a risk of missing out on even better holiday sales.

Or maybe not. An analysis from Boomerang Commerce last year found that major retailers' discounts and pricing for 1,000 popular products over Black Friday weekend and Cyber Monday was "nothing special."

Still, it doesn't hurt to hedge your bets by monitoring pricing of recently purchased items. Many stores will refund you the difference if you spot a lower price there, or at a competitor, within a set period after your purchase.

"It's going to be tough," said Edgar Dworsky, founder of advocacy site ConsumerWorld.org. "The policies vary from store to store."

You may have to act fast, he said – often, the match only applies if you spot a better deal within a week or two. Stores may also require that the deal be for the exact item (model number, color, quantity, etc.) and from a specific online or in-store competitor. Many specify that they won't match deals offered from Thanksgiving through Cyber Monday.

Of course, you'll also need to hang on to your receipt.

"The reality is, your mileage may vary," said Dworsky. "Really try to understand the terms and conditions so you don't get your hopes up needlessly."

If you made your purchases with a credit card, you may have more leeway to take advantage of holiday sale price drops, said Schulz. Several issuers, including Chase, Citi, Discover and MasterCard, offer "price protection" benefits for some or all of their cards.

"Price protection from your credit card can be a really good thing," he said.

Depending on the program, you may have as long as 60 days – or even 90 – to find a better price and file a claim. But like store policies, there's typically fine print on which purchases are covered and what kind of sales will be accepted for a match. Programs also cap how much you can get back on a given item and year.

Whether you're aiming to take advantage of a store or credit card's price match policy, set up price alerts to be notified of drops, said Dworsky. Apps like Slice and Paribus let you link your email or Amazon account to monitor pricing on past purchases.

Set reminders to do some web comparison shopping yourself ahead of a match deadline.

"Nothing is as good as being your own detective and checking prices," Dworsky said.