Question: I want a shopping app that tracks prices and alerts me when my favorite items go on sale.

If you want a shopping app that tracks prices and notifies you when you can buy what you want at the best price, Karma is a top contender. Karma is a browser extension and mobile app that can automatically apply promo codes, deliver cashback rewards, track prices and compare products at more than 100,000 retailers. It also can manage a unified wish list and recognize products from social media posts with AI technology. People can save an average of 18% per purchase, so it's a good option for savvier shoppers.

Another alternative is Beni, an AI-powered shopping assistant for secondhand products. Beni rounds up deals from more than 40 resale sites and offers features like favorites and price alerts. It covers brands like Gucci and Target, and works on personal computers with Chrome and Safari and on phones with Safari (iOS), with an Android version in the works. The service encourages environmentally responsible shopping while helping you find cheaper alternatives to new products.

If you buy from a variety of brands, SayF could be worth a look. The mobile extension uses AI to automatically identify and apply the best deals and coupons from more than 1,000 brands, including e-commerce sites like Amazon and brick-and-mortar stores. It's designed to save time and money by gathering relevant deals in one place, so it could be a good option for heavy shoppers.