I would personally suggest and recommend these apps to low-end smartphones, as they don't really contain any fancy design or advanced animation. Although, if you're curious about the interface, you can get them, too!
Nokia X Store
Nokia X Store offers some basic apps and games like Twitter, Skype, BBM Messenger and a few game. As you can see, app has a really basic UI. Nothing special.
Nokia Music does really look like the Stock Music Player in Android 2.3 Gingerbread. Again, nothing special. Just pure simplicity.
And again, nothing special here. These apps might be useful for your parents, or grandparents, as they doesn't really require any smooth animations or complex interface, though.
To install these, just download the APK file and install as a normal application. If that doesn't work, push the app to /system/app, set the permissions and reboot (this requires root access).
If you want to try the launcher out, you gotta be rooted. To install, download and flash the zip via custom recovery, reboot, press the home button on your device and choose your prefered launcher.