What version of Android are you using?
If you are using version 6 or later, you should be able to get the latest app from the Google Play Store.
If you have version 5.11, there is an earlier version of the eBay app that still works.
See here:
https://community.ebay.com/t5/Mobile-App-Android/Android-app-not-supported-on-older-systems/td-p/306...
If you have an earlier Android version, you can:
update your OS to Android 5.11 or later and use the eBay app
use a browser
use a third party app such as Fullscreen Tablet for eBay
use another device
