A few years ago, I got some little orange crates--the kind that clementines come in--at a garage sale, for free. I've made different uses of them, but here's the latest one:
(Ignore the walls. I've been experimenting with possible paint colors.)
Yes, its' a shelf! I didn't even have to drill holes in it as the crate has it's own little openings in the back. I had already painted it pink. Then I cut out a piece of felt to cover the back. No glue necessary: the wood is rough enough to 'catch' the felt.
Of course only light-weight things can go on this. But it makes a cute display!
PS--that white thing is a little crocheted marshmallow.