Online shopping can be difficult if you don't have full use of your hands, since it frequently assumes that you can tap or click your way through a sale. eBay could make internet purchasing more accessible to just about anyone who can use a phone, though. It developed an open source project, HeadGaze, that uses head tracking on the iPhone X (and, we presume, future iPhones) to enable hands-free shopping. It uses Apple's ARKit framework to create a "virtual stylus" that follows your head movements. When you combine it with an interface designed for shopping, you just have to look at the right part of the screen to scroll, add items to your cart and check out.
You should see the code for HeadGaze on GitHub. While it's geared toward shopping, eBay is betting that developers will apply the technology to other apps and experiences. You could walk through a recipe without covering your phone in flour, or launch an app when you're holding a bag in one hand. There's more coming from eBay, too. It's currently working on an eye tracking interface that could lead to more complex hands-free gestures and might help locked-in paralysis patients use mobile devices.