I found this nearly FREE idea in the ancient place of the flowers, Xochemilco, off the beaten path in Mexico. Holding up the canvas awning were wood posts decked out with ordinary tin cans. They use canned milk there with remnants of some labels still visible. Some cans were nailed on. Others had little wire bucket handles attached to the top that would hang on the nails so they could be taken down or changed. Note how the cans are placed one directly above another. That way when watered from the top the, drainage waters the can beneath it. Planted with donkey-tail succulents, what little water it needs is recycled for maximum value.