How do I get notified when something is back in stock?

Some online stores offer a subscription service to get notified when your desired product is back in stock. Most of them inform you through an email and some through a text message. All you need to do is sign up by entering your email address or a phone number for the notification widget on the page of your store. The only downside to a back-in-stock notification subscription is the bulk of marketing emails and notifications.