The coroplast plastic does take up more room and it is a little pricy. We always recycled lawn signs when I worked on political campaigns because we never had any money to spend. I would think twice about removing them from private property, but if they are on a public right of way, go for it.
Standing up is the way for me, so I buy fewer duplicates and can see what I have. And the fabric I wanted was always on the bottom of the pile.