There are countless Microscope-Stands you can buy, more or less usable. But for all 3D-Printer owners it's a breeze to print one. The additional screws, nuts, tubes etc. are mostly available in your Hardware-Store.
The Macro Images come from a Test Cube, Layer height = 0.25mm, Filament = PLA.
This Stand is optimized for the 5MP USB Microscope from adafruit
http://www.adafruit.com/products/636 but you can easily adapt it for others USB Microscopes.
1x Alu Tube outside dia 16 mm, inside dia 14 mm x 130 mm long.
1x Alu Tube outside dia 12 mm, inside dia 10 mm x 60 mm long.
1x Alu Tube outside dia 8 mm, inside dia 6 mm x approx. 14 mm long.
1x Threaded Rod M5 x 170 mm long.
1x Bearing 608ZZ or similar: inside dia 8 mm, outside dia 22 mm.
3x M5 Nut.
1x 5mm Washer
1x M5 Hex Nut Nylon Locking.
1x M4 Bolt x 14 mm.
1x M4 Nut.
1x M3 Screw x 8 mm.
1x M3 Nut.