Once you have Wallpaper Engine, the wallpapers themselves are free, so it's really worth a shot if you want something unique.

The wallpaper ... the best places to find it. Wallpaper Engine is a paid app on Steam, but it more than justifies the $4 you'll spend on it. It gives you access to thousands of animated wallpapers ...

If you are one such anime lover ... were some of the best sites where you can get live wallpapers for free. There are some other honorable mentions such as Wallpaper Engine or Rain Wallpaper ...