Check out this 3D printable florescence microscope with filter wheel, digital acquisition, and temperature control! All for less than half a grand. Dr. Peter Foster recently made one of these himself so we have at least one solid positive user experience with the device. However Peter says he took a shortcut with the illumination LED and never really got the florescence to work adequately,
http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2002702