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Attention, online shoppers: This free app can cut your final bill

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

priceblink-for-galaxy-fit

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

Rick Broida/CNET

True story: I recently 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 Galaxy 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 follows me around the interwebs, alerting me to better deals elsewhere. 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, and it's compatible with the desktop versions of Chrome and Firefox. I know: I say the words "browser plug-in," you say, "Smell ya later!" Which is weird, because it's not the 1990s. 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.

Want to add a product to your wish list? Just click the heart icon in the toolbar. You can also see a product's price history -- very valuable information to have -- by clicking the line-graph icon. 

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.

Concerned about privacy? According to the tool'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."

A few caveats

I'm fine with all that, but I do advise using caution when relying on this or any other price-checking tool. For one thing, make sure that when you click a PriceBlink link, you end up looking at the exact same product at the next store. With TVs, for example, there can be a lot of slightly different models within the same series. There's also the chance it'll steer you to a used or refurbished version instead of a new one, which happened to me a couple times.

You also want to make sure you end up with reputable seller. While I was viewing the AirPods ($159 at Apple) Pro at Best Buy, for example, PriceBlink pointed me to an eBay seller offering the earbuds for $50 less. Great, right? On closer inspection, this seller had zero ratings, and the estimated ship window (from China) was between three and 12 weeks -- two big red flags. Pass.

As long as you're careful, though, PriceBlink really can save you 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

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