There are many good uses for a 1st Generation iPad, including watching Netflix and playing casual games. The trick is getting apps that only support a later version of the operating system on the first generation iPad. Most newer apps only support iOS 7 or up, so the current version of the app won't work on the original iPad. There's a way to get an older version of the app onto your iPad, but for this to work, there must be a version of the app that supports the older operating system. How to download apps to the 1st Generation iPad: It is recommended to only try this with free apps like Netflix so you don't waste money trying to get an app that won't work on your iPad. Launch iTunes and verify that you are signed into the same Apple ID as you use with your iPad.
You can view these settings under the 'Store' menu.