I found this great, OLD toolbox for $2. I knew I wanted to use it as a planter when I bought it. I made a frame out of 2 x 4's and added legs. Painted it up, screwed the toolbox onto the legs and drilled holes in the bottom for drainage. I planted it with herbs and painted old silverware for plant markers (sorry-they are hard to see).
I screwed two pieces of wood on the back ( see it there in the space?) so the lid would stay open and upright and would not fall back. I considered painting the inside of the lid with chalk paint, but I decided I liked the way old wood looked.