I had a custom cabinet built with the exact dimensions for the trash drawer. The cabinet guy slid it in the opening he made for it, but did have to put a couple of thin slats underneath to make it level.
In my opinion it's a built in unit but if you really wanted to I'm sure you could use it as a free standing unit. I would still put a case around it, you could easily build something out of wood.
I did not use screws it fits tight and sets on the floor base and it works out fine but if you need to anchor it take out a draw and drill hole in the side at the top screw it in and reinstall the draw
