I am a technology teacher at an elementary school in a small town in BC.  Here is my submission.

1) Form: The design can be printed in any colour and a mismatch of colours to suit user preference. The design is sleek and simple.
2) Function: It may seem trivial but the bane of every teacher and student is the water bottle falling off the desk and just generally getting in the way.  This removes it off the desk and attaches in to the desk legs.  
3) Quality: We have had these in our school for a year and no problems yet!
4) Sustainability: If one piece breaks it can be easily 3D printed and replaced, no need to throw away the entire object as it is made of multiple pieces
5) Low price: Cost to print is around $10, and that is with high quality ultimaker filament, it probably could be made even cheaper.  Print time is about 6 hours with a 0.8 nozzle.

check it out in action here