You can only use your Horizon EXTRA Benefit card for online purchases at HorizonExtraBenefits.com or using the myTotal Benefits mobile app. Using the browser or mobile app, select the OTC Catalog , or OTC Grocery (if eligible) to open the details page, then scroll down and click the Shop Now button. On the website, you can also click the Shop OTC Catalog link at top of page and on the myTotal Benefits mobile app you can select the Shop OTC option on the main menu.