Getting the best possible deal is important to consumers like Maria Smith.   The busy mother of four loves to save with price matching.

"Just this week I bought a toy, saved three bucks, bought my coffee that day," she said.

Undercover cameras show what happens on the price matching frontlines.  For example, an electric screwdriver at one major chain was $99.  Then, when its bar code is scanned with a price matching app, an online retailer was offering it for a little less, at $94.99.

When brought to the attention of the clerk and supervisor at the major chain store, neither knew what to do about the difference in price. However, at the customer service desk, although the store's policy says it doesn't price match online retailers, the clerk did agree to sell the electric screwdriver for the lesser price.

"Some employees will stick exactly to the script as corporate policy writes when it comes to price matching, others will go out of their way to help shoppers," explained Louis DeNicola with Cheapism.com.

That's what happened in another undercover example involving a Blue Ray player.  At the very same chain store only two miles away, the same Blue Ray was a lower price.  But, that chain's policy was only to price match with online competitors and not their own stores.  So, the clerk checked online and found a retailer offering an even better deal: $50 off.

"Having an employee that knows the rules can make all the difference," said DeNicola.

Deal website Cheapism.com warns sometimes stores play sales hardball. 

"Although you might see a television that's 42 inches, it has the exact same specifications between two different stores, you'll find out that store A has a very specific model number because they've moved the power button to the left side you won't be able to price match it in store B," said DeNicola.

The only time there wasn't a savings during the undercover price matching scenario, was in a store that only price matched with certain stores.  In trying to get a lower price on a computer monitor, the clerk pulled up an internal list of shops they'll price match with,  and the store with the lower price was not one of them.

Experts say businesses try to strategize their pricing policies, but the marketplace is constantly changing. 

"Retailers must be able to react in the moment to a particular customer situation, and on the fly figure out how to become competitive with either somebody next door or somebody around the world," explained consultant Allen Adamson. "And that requires their front line; people who are working in the store, working with customers need to be empowered like never before."

Smith says if she can't get the deal, she looks for the exit.

"If the store doesn't match the other retailers price there times when I have walked out and not bought the item," she admitted.

The major big box stores in this undercover price matching test all said price matching is important for them to stay competitive.  The store where the employees didn't know the rules did apologize.

Some stores will also match prices a week or two after you bought an item if you find a lower price elsewhere, just bring in your original receipt, and proof of the competition's price.  

Check out major retail chains' price matching policies here.