I bought these at a garage sale but you can buy them in a craft store. This is one of the items I used.
As you can see in the photo I taped a stack of these door hangers together. I'm getting ready to cut them down. You can see the line I drew on the top one.
These are the size that the pieces are after cutting them down.
Next I tapped them together and cut them length ways.
All you need to do now is measure each piece to the length you need them to be in each area of the bottom of the walls. Then add Popsicle sticks around the wood and down the center to look like wainscoting. In the picture you can see the pieces on the bottom of the walls.
This is another view.
Here's another view. I painted them off white. The top half of the wall is scrap booking paper it makes great wallpaper and you get a lot more choices. You can also use these for shutters on a window.