Interchangeable photo display using clothespins. This would be a great way to display photos that you love, but won't really stand on their own in a frame. I like it better than the pre-made multiple photo frames--more my style and also so easy to switch things up!
If you dont have the money to buy expensive wall decoration, recycle old frames, paint everything in one colour (or complementary colours) and make a composition with it. Suits in a minimalistic house, even with baroque frames.