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Attention, online shoppers: This free app helps you find lower prices

A must-have for Amazon shoppers, the PriceBlink browser add-on makes it easy to comparison-shop.

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PriceBlink alerted me to a better deal elsewhere (in this case eBay) on the same product.

Rick Broida/CNET

A while back I wrote about the Samsung Galaxy Fit, a popular fitness band that was on sale at Amazon for $69. That $30 savings made for a pretty good deal. But then I noticed the PriceBlink bar at the top of my browser -- it had found the exact same item (new, not used) at eBay for $51. And it wasn't an auction listing; that was the Buy It Now price.

Had I actually been shopping for the Fit, I'd have saved $18. Not too shabby given that my total effort was zero. That's why I installed PriceBlink in the first place: It alerts me when there's a better deal to be had. It's definitely a useful Amazon hack, but it works at some 4,000 other online stores as well.

PriceBlink is a browser plug-in, one that's compatible with the desktop versions of Chrome and Firefox. I know some users balk at plug-ins, but I think the potential benefits outweigh any slight performance hit (and I didn't notice one to speak of).

Read more: This Amazon shopping hack can save you 70% or more  

Once it's installed, you just shop like you normally would. For any given product you're viewing, PriceBlink will indicate if there's a better deal elsewhere or, if not, the next best price. You can also click the Compare Prices pull-down to see exactly what other stores are charging, tax and shipping included.

Thankfully, the service recently upgraded its algorithm to make sure it's comparing the exact same product in the exact same condition. In the past you might see a lower price indicated elsewhere, only to find that it was a used or previous-generation version. (Even so, you'll want to make absolutely sure you'll still getting exactly what you thought you were getting.)

Want to add a product to your wish list? Just click the heart icon in the toolbar. PriceBlink's other magic trick is finding coupon codes, though it doesn't automatically apply them for you the way some other coupon tools do. Indeed, you often end up having to open one or two additional tabs just to get to a code, which is annoying. What's more, the tool no longer offers price-history information, which was useful to have.

If you're concerned about privacy, check out PriceBlink's FAQ page: "The PriceBlink add-on sends a request to our servers that contains information about the product you are browsing. PriceBlink does not collect or store any personally identifiable information."

I continue to find PriceBlink a useful shopping tool, one that can indeed help you save money. If nothing else, it can save you time: You don't have to visit one store after another after another to see which one has the best price.

Your thoughts?

Read more: 4 surprising ways to get cash back

Originally published earlier this year. Updated to reflect new information.

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