I was in a department store the other day and they had a display where they had four plain cylinder vases attached to a wall with some simple silk flowers in them. It was just a prop in the home department, not actually something they were selling, but I tucked it away for future use. I'm sure it would be easy enough to do with cheap items from a craft store.
Another easy idea: I have a bunch of saucers hanging on the wall in my dining room. I stole the idea from a B&B where I stayed years ago. You can pick up single saucers for just $1 or $2 at junk stores. If the cup is broken most people don't have any use for them. Just add some plate hangers and you're set!