Depending on whom you talk to, online shopping is expected to increase anywhere from 13 percent (according to IBM) to 20 percent (according to Omlis) during the five-day period of Black Friday shopping.

All the experts agree that the rise in mobile browsing and shopping is an important part of that increase.

Almost 50 percent of shoppers use their smartphones or tablets to do price and feature comparisons for the products they want to buy, according to data from IBM, and about 24 percent are actually making purchases from their smartphones and tablets. The real trendsetters (mostly younger ones) are using their smartphones to pay for purchases.

Since mobile devices are playing an increasingly important role in holiday shopping, here are the basic apps you will want to make sure you have on your phone when you’re shopping. Many shopping apps have similar features and functions, so be sure to choose the one that works best for you.

An app for price comparisons: This is what most people are doing on their mobile devices, so it's important to choose the one you really like. If you're already in the store, you'll want an app that can check prices online and in physical stores. Apps like RedLaser and ShopSavvy let you scan items to compare prices from online and offline retailers. For online shopping, apps like PriceGrabber do comparisons across online retailers. Wal-Mart offers its Savings Catcher program (https://savingscatcher.walmart.com/), which lets you scan your store receipts. If it finds a better price, you get the difference on a Wal-Mart gift card.

An app that gives you coupons or cash back: Hate that feeling when you make a purchase and later spy a valid coupon? The power of geo-locating helps Shopular send deals from your favorite stores to your mobile phone when you need them. RetailMeNot does the same by sending alerts to your phone when deals are nearby. Users of The Coupons App can check for coupons from favorite stores before heading out, then have them scanned from their smartphone at checkout. Since cash back is almost as popular as coupons, check apps like Ibotta, which lets you earn cash through rebates on items such as groceries, apparel or electronics.

An app that helps you sort through the best Black Friday deals: Stay on top of the hottest Black Friday deals with apps like BuyVia, which also offers price comparisons. Most of the deal sites that track Black Friday sales and other deals year-round also have an app for Black Friday. A new feature on the FatWallet Black Friday app lets shoppers compare year-round hot deals to Black Friday ad prices before making a purchase decision. Also check Brad's Black Friday (http://blackfriday.bradsdeals.com/app), Black Friday Shopping App (https://blackfriday.com/mobile), and the Black Friday app from Dealnews.com.