Getting the lowest prices on Black Friday usually requires an early store arrival and fast feet, but this year shoppers may find that their smartphone is the best savings tool.

Why are retailers ruining Thanksgiving?

Amazon made waves last year by offering an app that compares competitors’ in-store prices with its online deals. This year, traditional retailers are fighting back with apps of their own. Think of Black Friday 2012 as kind of “The Revenge of the Retailer,” says Brad Spirrison, managing editor of review site Appolicious. Shoppers also have plenty of price comparison and review apps to help them further determine what to buy, precisely where, and when. Analysts expect that people will be taking advantage: Tablets and phones are expected to account for 24% of online traffic on Black Friday, according to software maker Adobe’s holiday forecast. Over the entire holiday season, 70% of shoppers say they plan to use their smartphone while shopping, reports Deloitte.

Finding deals on the spot requires some advance preparation, however. Malls and stores don’t always have accessible Wi-Fi networks or even much in the way of cellular signals, so downloading deal apps is best done at home, Spirrison says. Slow connectivity can also make using the apps time-consuming, so he recommends doing the bulk of the deal-comparison work in advance too.

For maximum savings in stores, stock up on three types of apps:

1. Price-comparison apps

Nearly 40% of smartphone owners use their phones for in-store price comparisons, according to Nielsen, and experts say it’s still a smart strategy for Black Friday. “Browsing pricing and availability is just part of the game now,” says James Brown, director of merchant accounts for PriceGrabber.com, a comparison site. Most stores suspend their usual price-matching policies on Black Friday weekend, but a few holdouts — including Kohl’s, Wal-Mart, J.C. Penney, Home Depot and Staples — will still match competitors’ prices with proof via a print ad or online screenshot. If the store refuses to match a competing price, you can use the app’s info to decide where to go next or, in the case of apps like Price Check by Amazon, order online right from your phone. Which app to pick? See our breakdown of the five top apps (5 Top Price-Compare Apps) for comparing in-store and online prices.

2. Product-review apps

Some Black Friday sales aren’t worth your cash. Keep impulse purchases in check by looking up expert and consumer reviews while you wait in the checkout line. Spirrison suggests having at least one app specific to Black Friday, such as Black Friday by BradsDeals or Black Friday by FatWallet, which point out some of the hotter deals and assess how sales stack up. Comparison apps including those from Decide.com and Price Check by Amazon also offer expert and user reviews, respectively.

3. Discounts apps

Mobile couponing has been on the rise, and many retailers are beefing up their deals for the holiday season. (See Mobile coupons: Worth the screen time?) Macy’s and Sears have both promised exclusive deals for app users, for example, and Wal-Mart has said it will give early access for some Black Friday and Cyber Monday deals to shoppers who download its app. American Express also recently launched a Mobile Gift Cards app, which lets cardholders redeem points for mobile gift cards that can be used immediately at stores including Gap, Old Navy, Pottery Barn and Williams-Sonoma. Consider downloading the app for each store you plan to visit — it’s easy enough to delete them after Black Friday. It may also be worthwhile for shoppers to try locator apps like Foursquare and Shopkick: Last year, stores such as Toys “R” Us offered exclusives for shoppers who virtually “checked in.”