This is THE simplest and cheapest amp ever. Just two materials and one is your iPod (or mp3)!! The quality might not be as good as the other Instructubles which take a lot of complicated materials or store bought speakers but it's decent and cheap. :)
Step 1: Materials
~A metal or tin box
My box was a candy box from Disneyland; my friend gave it to me. You can use any kind of tin container though, like a cookie box...
Well, there's technically no steps....you just put your iPod in and crank up the volume! It might sound hollow, but hey, it's free....
Step 2: (this Isn't Actually a Step)
Enjoy your free (or cheap) sound amplifier for your iPod/mp3!! If you don't believe this, turn the volume up and listen to anything then put it in the the tin and compare it. This can also work with earphones if you want to use your iPod while listening to music; just plug in the earphones and then put them in the tin, and if you want to make sure that they don't fall out you can always poke a hole in the side of the tin to put the wire through and shut the lid....
PLEASE VOTE I'LL BE JOINING THE GREEN CONTEST!!!!!! :)