If y'all want to make your own,
All Electronics has components for black lights that are good for small stuff like models or art pieces.
UV Fluorescent Lamps
diameter-X-length in millimeters
3x25 $8.25 #UV-325
3x50 $8.50 #UV-350
3x100 $10.75 #UV-3100
You'll also need some power inverters, which they carry for around $10 each. These black lights are tiny, which is bad if you want to fill a room, but good if you're making something that you want illuminated. They also have regular white ones, as well as colored (red, yellow, orange, green, blue).
Shipping runs $5/order.