As retailers continue crowding the marketplace, it has become both easier and harder than ever to find the best deals. Plus, thanks to the miracle of "dynamic pricing," many stores now use algorithms to track—and change—pricing down to the minute. What this means is that you have every reason to use every tool in your toolkit to one-up that merchant who is trying to convince you no price is lower. Each of these apps gives you the power to keep your finger on the marketplace pulse every time you shop.

1. Smoopa

Consumer Reports, USA Today, The Wall Street Journal, TechCrunch, and others all rave about Smoopa, the price-check app that rewards you for using it. Each time you use Smoopa, you earn. Then, redeem your earnings as a rebate check or a gift card, or choose to donate your earnings to a charitable cause.

Smoopa also supports these extras:

  • Multiple search options: You can search by barcode scan or manual entry.
  • Personalization: You can personalize your feed and build a network of like users to find more great deals.
  • Contribute: As you submit your price finds, everyone wins!

2. Scan Life

Scan Life can help you get the best deal without ever leaving your house. You can do price comparisons locally, online, and even purchase from the retailer with the best deal right from the app itself—no driving required!

Scan Life also offers all of this on top of its powerful price-comparison tool:

  • Coupons and deals: You can cash in on coupons and deals as you’re conducting price comparisons.
  • Earn points: You can earn points towards useful gift cards.
  • Product extras: You can even learn about product accessories and the nutrient content of grocery items.

3. Consumr

Consumr has earned kudos from InStyle magazine, The New York Times, USA Today, The Wall Street Journal and others. The free app covers a vast array of categories from groceries to appliances, beauty to baby.

Consumr also offers you these perks:

  • Prizes: When you offer your product ratings and reviews, you earn points towards valuable and fun prizes.
  • Deep intel on products: You get much more than just price comparisons when you use Consumr—you can also read multiple reviews from other consumers who have already bought and tried the product.

4. The Find

This app hones in on only what you absolutely want and need to know by scanning local and online deals only. The app will send you customized price alerts to give you first dibs on a low-price item.

The Find also offers these perks:

  • GPS tracker: The Find can track you by GPS and give you deals nearest where you are.
  • Sync with online site: If you prefer to make your purchases from home, deals you find on the app will show up when you visit the online site.

5. ShopAdvisor

If you’ve ever wondered if timing matters when getting the best price, ShopAdvisor has the answer—yes. This app continually watches prices as they fluctuate, reporting in with alerts when your desired price is available.

Also benefit from these extras:

  • Reminders: If you need to shop for a specific item at a specific time, ShopAdvisor will send you a reminder.
  • Pricing history: You can see the entire pricing picture for an item—past, present and trends.

6. PriceGrabber

PriceGrabber scans pricing in 160+ U.S. cities to find the best deals online and offline, including popular mega-deal sites like Groupon and LivingSocial.

PriceGrabber also offers this extra functionality:

  • Bottom line price: Gives you the final price including tax and shipping.
  • Price alerts: You can set up a price alert to reflect your desired price and get an alert when a retailer meets it.
  • Driving directions: When you find the product at the price you want, you can even get directions from the app!

7. Amazon Price Check

Amazon Price Check is a free app that helps you ensure you’re always getting the lowest price—even if it’s not on Amazon! Not only can you find the lowest price, but you can also share your findings with other users (and benefit from their findings).

In addition to price checks, Amazon's app also does all this:

  • Multiple checking options: You can now price check by scanning a code, snapping a photo, speaking the product name into your phone, or typing in your search request.
  • Text and email supported: You can text and email your finds to other users in your network.
  • Integrates with Amazon's other services: You can access Prime and 1-Click ordering using the app to be sure you don't lose your deal.

8. Shop Savvy

Shop Savvy is yet another powerhouse price-comparison app guaranteed to make you think twice before making an impulse purchase without checking it first.

Shop Savvy also gives you these extras:

9. Red Laser

More than 27 million users use Red Laser to hone in on rock bottom deals and savings. Feted by the Today Show, CNN, The New York Times, Fortune, and others, the app is equally useful for brick-and-mortar and online shopping.

In addition to the things you know Red Laser does, check these extras out:

  • Local deals: Gives you breaking intel on new local deals and coupons.
  • Loyalty cards: Stores all your loyalty cards in one place.
  • Favorites: Saves your favorites for future reference.
  • Price comparisons: Helps you compare prices between retailers whether they are online or offline by manual lookup or bar code scan.