NEW YORK, N.Y. – It’s a shopper’s nightmare: Buying something, then seeing it cheaper at another store. Thanks to price-comparison apps, there’s no need to guess if you’re getting the lowest price.

All you need is a smartphone and some downloaded apps.

Smartphone owners have been using the price-comparison apps for the past couple of years. But they’ve improved a lot recently. They’re faster and easier to use than earlier versions. They’ve become a bigger threat to retailers who don’t want customers using their stores as showrooms.

I have been using Inc.’s price-checking app for about a year now and have always found the prices on the app lower than at a store. But I’ve never tried other popular apps by Google Inc. and eBay Inc.

I wanted to see if they could get me to even lower prices. I’ve been looking to buy a fruit and vegetable juice extractor. It’s been costing me nearly $7 for a 20-ounce cup of kale juice at my neighborhood juice bar. I think I can save a lot of money by doing it myself.

The target: a Cuisinart juice extractor, because it wasn’t too big and looked easy to clean. I saw it at a Bed Bath & Beyond store in New York, where it cost $149.99. I took out my iPhone and started scanning the barcode from the box.

I used five different apps. They were all free, and all are available on both iPhone and Android phones. All the prices listed below are for a new Cuisinart juice extractor, though some of the apps will give you prices for used or reconditioned items, too.

To find the best deal, I realized that you need to have more than one of these apps on your phone. Here’s the lowest price each app found:

GOOGLE SHOPPER (Lowest price: $131.99)

Google wins for finding the lowest price for the juicer. I was surprised to find that the best price was at a physical store and not online. Macy’s had it on sale that day for $131.99. (I went to Macy’s to make sure it actually was that price, and it was.) One bonus is that the app also makes it easy to call the store or put it on a map if you need directions.

AMAZON MOBILE (Lowest price: $135.85 ($124.36, plus $11.49 shipping)

This app searches for prices only within It doesn’t show any prices for local deals. That said, it had the second-lowest price, even with shipping. You do need to have an Amazon account to buy from the app. But if you already have one, purchasing from it is easy, and done in one click.

PIC2SHOP (Lowest price: $135.85 ($124.36, plus $11.49 shipping)

This app found the same price from Amazon and linked to the Amazon website. The app does search for nearby store prices, but it wasn’t as extensive as the Google app. It only found one physical store price, but it wasn’t cheaper than the price available on Amazon.

REDLASER (Lowest price: $148.95)

This app is owned by eBay Inc., the online marketplace. The lowest price was from an online retailer. Even though this app didn’t find the best price for the juice machine, it’s worth downloading. You can scan in loyalty cards for certain supermarket and drugstore chains, so you hand over your phone to the cashier instead of carrying a bunch of cards. It lets you buy items within the app from retailers such as Toys R Us and Best Buy and also posts coupons.

MILO (Lowest price: $149.99)

This app is also owned by eBay. This app shows prices for brick-and-mortar stores, not online retailers. The lowest price it found for the juice machine was at a Macy’s store, but it didn’t pick up the sale price of $131.99 like the Google app did. This app matched the price of the item at the Bed Bath & Beyond store, but it’s still worth downloading if you are looking to buy something right away and can’t wait for it to be shipped.

Hardcore deal seekers will want to download all five apps. But if you don’t want to spend the time scanning barcodes five times, at least download these three: Google Shopper, Amazon Mobile and RedLaser.

Google Shopper saved me $18, the most of the bunch. Amazon’s came in a close second. I’m going to continue to use it, because it’s convenient to buy from the app. RedLaser’s price was just a dollar less than Bed, Bath and Beyond’s, but the app has more features than others. I’ll use the loyalty card scanner and check for any coupons.