I love this kind of news. With inexpensive materials, you are able to convert your smartphones or tablets into a powerful microscope that is capable of viewing anthrax spores, plague cells, parasites in blood samples, protozoa in drinking water, salt grains and flower petals and more in great details.
From PNNL (Pacific Northwest National Laboratory), the material cost is less than USD1. Do note that you will need a 3D printer and a small glass bead. PNNL has everything you need, from files to print the 3D model to links for you to buy the glass beads in various sizes (for various magnification).
If you are interested, head over their website to check out what you need.
What I think is the most interesting is that those working in the field (doctors, law enforcers and etc) can easily take out their smartphone with this inexpensive attachment to take microscopic pictures of evidences, powder and etc and send them to a professional for immediate evaluation. This, in my opinion, is the most valuable aspect of this project.