I finally picked up some entry-level studio monitors (M-Audio AV 40, $75 for the pair via Craigslist) in preparation for mixing my acoustic project's first EP. It was immediately apparent that they needed to be raised off my desk about 8 inches.
Conveniently, half cinder blocks are 8" cubes, dirt cheap, and concrete is pretty acoustically "dead."
The materials: two half cinder blocks, some self-adhesive felt feet to project my desk surface, and a can of Plasti Dip (I actually ended up using about 1.5 cans):
Brush off any concrete dust, and start spraying. After 3 coats of 'dip:
After 5 coats:
In use (yes, my desk is shitty - building a new one is next on my list of home studio projects):
I chose Plasti Dip rather than regular paint since I thought it might bond a bit better to the gritty surface of the concrete, and it seems to be working well. The improvement in sound is incredible - the monitors are now at the right height, and much more isolated from the desk.
Total cost: under $15. You could do it for under $5 if you used cheap spraypaint instead of the Plasti Dip.
That actually looks really good.