This is the best coupons app for Harbor Freight Tools The app collects a lot of coupons. Including the monthly coupon book. You can find whatever you like in this app. HFT Coupons. Features: 1. Coupon Overview 2. Free Coupons 3. 20% Coupons 4. Search Coupon 5. Barcode scanning 6. My Favorites 7. Share coupons.