I have a confession to make, so let me get it out of the way up front. I sometimes shop in brick-and-mortar retail stores, find what I'm looking for, then stand there with my phone and buy it online.

I feel really bad about it. But if, say, a book is $10 cheaper online, and they deliver it to my door in a day or two without me having to wait in line, why would I buy in the store?

I do this a lot with books, but also electronics and even groceries.

I always feel guilty about it. After all, the store has gone through the trouble and expense of finding a location, paying the lease, hiring employees and stocking their shelves. I take advantage of their investment, yet don't contribute with my purchase.

Am I helping to drive them out of business? Am I being a hypocrite for enjoying services I am unwilling to pay for? Am I doing something akin to stealing?

While I ponder these questions, I realize that I'm not breaking the law, or even breaking any company rules that I'm aware of. Retailers (both online and offline) are engaged in a contest with customers to see who can get what they can from the other.

Many companies are happy to lay off domestic workers and find cheap-as-possible labor abroad. If the product I like isn't popular enough, they won't hesitate to discontinue it no matter what I want.

They pollute the airways and roadsides with manipulative marketing without our permission or consent. In other words, they use our space and time and attention. Why can't we use theirs?

Besides, the practice of buying online what you find in physical stores is part of a larger evolution of retail. Progress is good. The market is finding the most efficient delivery system for each category of goods.

Some products, like books and music, are far more efficiently bought online. Others, like clothing, milk and bread are better when bought in real life. The smart companies are doing both, offering the convenience of retail shopping and also the huge selection and discounted pricing of online buying.

If purchasing habits never evolved, we'd all still be buying trinkets from traveling peddlers. Ruthless opportunism by consumers has created millions of jobs and transformed modern life. So when I find things in stores and buy online, I'm not just kicking mom and pop while they're down. I'm also helping the economy.

There. Now I feel better.

The truth is that buying online what you find in stores is an area of perfect grayness. I asked friends on Facebook , Buzz , Quora and Twitter whether doing this was ethical. Most said it's fine. Some said it's wrong. Both views are valid.

My own opinion is that if you're doing to do this, do it right.

Until recently, my find-in-store-but-buy-online methods were primitive. I would typically just snap a picture of the desired object and email it to myself. Later, I would be reminded by the e-mail, then use my PC browser to find the best retailer online.

Sometimes, when I had time to kill, I'd fire up my phone's browser and make the purchase on the spot. This was easy with online retailers like Amazon.com, which already has my credit card information.

But now I've discovered a new category of resources that turbocharges the whole process of buying online what you find in local stores.

The best of the lot is something called Google Shopper . It's a free app for Android and iPhone that performs some amazing feats. Just point your camera at the product and click a "Scan" button. More often than not, the app will correctly identify the product by its appearance, or by the barcode if it finds one.

Google Shopper will then list both online and local stores that offer it, along with prices and other useful information. You can even just say the name of a product, and the app will recognize your words and find the product just as easily.

Google Shopper is optimized for media, like books, games and movies. But it does pretty well with other products as well, including groceries.

The free Amazon Mobile app for Android and iPhone does something similar, but works only with books. You just scan the barcode on a book, and Amazon will bring you to a page with book information, and the familiar Amazon buttons to "Buy Now," "Add to Cart" and "Add to Wish List."

Amazon Mobile doesn't let you comparison shop, or identify products that don't happen to be books. But for buying books on Amazon that you find in retail stores, there's nothing better.

Shop Savvy is great with groceries and other random products. It scans barcodes only, and tells you where to buy them online and locally. You can read and write reviews. For foods, it even gives you a "nutrition grade."

There's no need to choose between these three apps. They're all great in their own ways, and they're all free. I use them all.

There are other free apps available on both Android and iPhone that read the barcodes of products, then facilitate online purchase. And I'm sure there will be many more to come.

Is it abusive and unethical to shop in old-fashioned stores, find the product you want then buy it online with your phone? Well, that's up to you.

But if you do it, make sure you use one of the new free apps that streamline the process and help you save a lot of money.

To miss out on this incredible technology would really be the crime.

Mike Elgan writes about technology and tech culture. Contact and learn more about Mike at Elgan.com , or subscribe to his free e-mail newsletter, Mike's List .

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