The other day I purchased two decorative birdcages from The Reject Shop for $15 and $10 (one small, one large).
I had been on the lookout for a nice cheap but decently sized birdcage for ages, so they were perfect, and they were on special!
All I did was paint them white. I used one spray can of paint (approx. $8)for two of them, and then hung them in a tree in my garden.
They look really pretty now! There are also endless possibilities with what you could do for colours and things.... aqua would also be nice, or each one in a different colour. If they weren't going outside, you could also spray-glue material into the bottom of them, and of course, a nice bird outline covered in material sitting inside one would look lovely too!