[hat and bread]

Bicycle reed horn

Really simple reed instrument for about $2.
1) Buy a cheap plastic bicycle horn or similar noise maker. Rip it apart and take out the reed.

 

The reed should look something like this (this one is from one of those annoying party noise maker things, but they're all pretty much the same).

 

Bicycle horn reeds tend to look something like this:

 

Jam it in the end of any kind of hose. The longer the hose the lower the tone. If the reed encasing is smaller than the hose wrap some tape around the encasing until it fits snuggly inside the hose. Done! If you want cut some holes in the hose to add extra notes.