Plastic ziplock bag
Step 1: Fill the Bag
Leave enough empty space so the bag is still malleable, but has enough density to support a camera.
I recommend about 3/4 full.
Squeeze out any excess air, and presto.
Try it out.
It works like a dream. You have endless angles that can be made by simply shifting the rice around inside the bag, yet perfectly level images can be captured as well.