Jonathan Takiff: You can buy an app for that

 THE GIZMO: Even James Bond might be impressed by some of the smart and sneaky phone applications to help you shop this holiday season. The free, downloadable apps let you deploy a mobile-phone camera to capture coded information about a product, then make the smartest purchase decision.

REALLY QUICK RESPONSES: Point a smartphone camera at one of those artsy Quick Response symbols now decorating lots of packages and, with the right app, the screen is soon seized for an extended explanation/commercial about the item. Sure beats asking a seasonal sales person.

Things get a lot sneakier if the shopping app captures a product bar code. The software pulls up a list of other retailers and their prices for the same item. Sometimes it lets you make an instant purchase.

If this cute trend in spywork takes off, retailers may soon demand you check your mobile at the door!

DANGER ZONE: Maybe the most nefarious of the apps is Flow, launched this season by Amazon.com for the iPhone. Dazzlingly fast and accurate, it uses a multipoint recognition system (note all the dancing blue dots on the phone's screen) to ID a product from the bar code or even - get this - the cover art of an object you hold up to the lens. Works especially well with books, video games, videodiscs and CDs.

Maybe a whole second later, the phone screen confirms the item, offers access to user reviews and serves up a price quote from Amazon. Tap one more button to buy.

BEAM ME DOWN, REDLASER: One of the original product scanning apps, RedLaser offers instant comparison-shopping from multiple sources aligned with eBay, which acquired RL 17 months ago, and from Google, TheFind, Half.com, Milo.com and Best Buy. Available for iPhone and Android mobiles, RedLaser scans bar codes and QRs. The new RedLaser 3.0 edition adds features such as "buy mobile and pickup local," with Toys "R" Us as its first partner; "in-app" checkout using PayPal; categorized shopping lists you can share via Facebook, SMS and email; plus an archived listing of all the books, CDs and DVDs you already own.

SAVVY AND SAVVIER? Rival apps with similar names, ShopSavvy and Savvy.com, both have their selling (or is that buying?) points.

ShopSavvy lets you find items by keywords, as well as by bar codes. It searches for products in Europe and the U.S. And, for serendipitous fun, it lets you "shake" the phone to summon up a good deal in . . . something.

Currently in beta (test) mode at the Apple app store and coming soon to the Android marketplace, Savvy.com's most intriguing feature is the ability to track pricing on items you've already bought from a participating retailer. And here's the punch line: If the price drops, you can get a refund.

I tried this out with the purchase of a Zagg Invisible Shield for my iPhone 4S at Best Buy. With the Savvy.com app up, I used the smartphone's camera to take a picture of the receipt, then clicked on a tab to send the image off to who knows where.

Wasn't sure the thing was even working (the receipt image oddly locked on the screen). A few hours later, I got an official-looking post that accurately identified my purchase, showed both the current price and what I'd paid (in this case, both $20.99) and included the message that I was "price protected" until Jan. 27, with a Best Buy customer-service number to call for help.

Savvy.com also offers a "Deal Maker" option, letting you enter a "willing to buy" price on an item. I offered $5 for "Surrogates" on Blu-ray. The best price I found was $16.99, but if it does ever drop to a fin, I'll be duly informed.

Unfortunately, Savvy.com stinks when it comes to the "simple" stuff. But hey, it's in beta.

Participating retailers include Babies "R" Us and Toys "R" Us, Home Depot, Nine West, Urban Outfitters, Pottery Barn, Office Depot, Radio Shack and more.

APPLE OF YOUR EYE: As the name suggests, the Apple Store app is for all things, um, Apple, and works strictly on the iPhone.

First off, you can read about and buy stuff right on the app. The really wild feature comes into play when you enter an Apple retail store. Pick up an item, scan its bar code with the phone camera, then tap the "buy" button. Your purchase is now complete! Really.

Just put the item under your arm and walk out the door without a sales clerk ever getting involved. Apple is only letting customers do this with relatively inexpensive accessory items, though.

And odds are good someone guarding the door will ask to see the electronic receipt on your iPhone screen. But as an exasperation saver in a crowded store, can you beat this?