Scroll up to see what the bland, tan drop cloths used to look like. They each cost a buck and half at the local Wal-Mart. I found them in a bin full of quilting squares and they were the perfect size, but were basic fabric, so I had my crafty wife sew up the edges to keep them from fraying.
I also threw together four ponds. They are just MDF with sand glued for land and blue paint for water. The water got a couple of coats of glossy clear-coat to give them a little shine.