4) 120cm computer fan covers (I got mine from all electronics) -- about $1.20 each
9) 6in standoffs(other lengths will work)(I got mine from electronic goldmine) -- $.49 each
3) screws that fit into the standoff(10-32 in this case)(I got them from a local hardware store) -- around $1
3) nuts that fit onto the standoff(10-32 in this case)(I got them from a local hardware store) -- around $1
Total: about $10 (about 6.5 GBP)
Step 1: Base of the Shelf
2) Put the screw through the "prong" and into the standoff
3) Tighten the screw
4) Repeat 2 and 3 until you have 3 standoffs attached
Step 2: Next Two Selves
2) Screw the standoffs on
3) Repeat 1 and 2
4) Put the last fan cover on top
5) Put the nuts on
Step 3: FINISHED!
The pictures show some ideas of what you could put on it.
I entered this into the dead computers contest, so if you liked it please vote for it.