You may have seen the DIY altoids amp somewhere else, but this one is easier than the other plans I have seen. This project can be completed in one sitting, depending on how long that
sitting is and how precise you make everything. It will cost you about 10-15 dollars depending on what you have lying around the house. Sorry the pictures aren't up, I am having a problem uploading them.

Step 1: Time to Void a Warranty!

Tools:

-small Phillips head screw driver
-electrical tape or duct tape
-hot glue gun (optional)
-wire strippers (won't be mentioned, but they will come in handy)
-drill or dremmel tool (to cut through altoids can)

Supplies:

-cheapest cassette walkman you can find (get one without AM/FM, that requires more space, and it won't fit in the altoids can. It should cost around 5$, mine is a Durabrand model 820M...real high quality stuff here folks)
-altoids can (empty, eat up)
-toggle switch
-audio in jack (like what you plug your guitar into)
-x2 AA battery holder (side-by-side, not end to end )(x2 means holds two batteries, not two holders)
-extra wire (not neccessary, but will probably come in handy)

NOTE: If you don't use the same exact stuff I do, yours may not fit into the altoids can, if it won't fit, find another case, I recommend the cassette player case.

Take the tape player apart, do it carefully, you may need to know how it goes back together later. Get the chip with electronics out IN ONE PIECE. The motor and switches may be
attached, these will need to be removed in a later step, but first, you need find out how pressing the play button connects power to the amplifier. Follow the power wires from the
battery compartment, one of them should be interrupted, when you press the play button, it will become uninterrupted, this is where you will hook up the toggle switch, in the place of
the play button. Also, in my tape player, there was a switch labeled "bass boost", I had to cut a little of the case plastic to get the switch out in one piece, but I guess if you wanted, you could just remove it.

Step 2: No Turning Back

Now you need to find the magnetic tape reader and cut it off, leaving as much wire as possible attached to the amp chip. For thos of you who don't know, the magnetic tape reader is a little metal box, a little bigger than a pea, it will be where the magnetic tape on a cassette would be if you were using this tape player normally.

Step 3: Moment of Truth #1

Now, to the wires you removed the tape reader from, connect the audio in jack, the wiring worked the first time I tried it, I don't know if it is reversible or not.Hook up batteries to the power wires, plug in a guitar or whatever, turn the toggle to "on", plug headphones into the headphone jack (located somewhere on the amp chip), and make some audio input, i.e. kick the guitar strings with your feet because your hands are probably a little full.

Step 4: Moment of Truth #2

If it worked, hurray, if not, check your wiring, maybe switch the wiring of the input jack. So if it is working, you have another job to do, turn everything off, find the motor assembly, cut the wires (in the middle, incase you need to splice them back together) going from the chip to the motor, turn everything back on and if you still get sound, pat yourself on the back. Now get back to work. If it didn't work, then your amplifier is probably dependant on the motor wires, this means that you will have to either-

a.Figure out a way to bypass it on your own, cause I sure don't know

or

b.Just leave them on and mount the thing in somthing bigger than an altoids can

either way, if it doesn't work without the motor, the rest of this instructable can't do much for you. Sorry. You're on your own. Good luck in your venture into the unknown. You
will be in my prayers. You are a brave explorer in uncharted territory.

Step 5: I Just Cant Duit, I Got Ta Have Moor Power!

If you are still here, then you have a working amp, with no motor attached (that's a good thing), and no case. If somthing I just mentioned is wrong, go back, reread, and find out
where you belong you lost puppy. Now try to fit the battery box in the altoids can (don't have the batteries in the can, it could short out on the metal of the altoids can), it should be just a little too big, file it down on the ends and corners so that it will fit in snuggly, and so that it will be as far over to the side as possible (saving as much space as possible is extremely important). Once it is satisfactory size, remove it.

Step 6: Found This Part Out the Hard Way

Now take the altoids can (make sure it is empty, mint dust, electronics, bowling trading cards........altoids) and observe that it is metal, now, if you are on this site you are probably quite aware of the unexplicable phenonmena of metal conducting electricity, this is not such a great thing to be putting naked electronics and batteries in soooooooo, we insulate it. Coat the inside of the bottom of the can (you can do the top if you are feeling ambitious) with electrical tape or duct tape.

Step 7: It Begins to Take Shape

Time to move in.
Wedge the battery box in the can, and make sure it is all the way over. Put the chip over to the other side, make sure the headphone jack is up against the wall of the can. In the space between them, drill a hole to house the input jack, on the top of the can, make a hole to house the toggle switch, on the side wall of the can, make a hole that meets up with the headphone jack.

Step 8: Wiring Wiring Wiring

Wire everything together, chip to input jack, battery box to chip and toggle switch (+ goes to toggle, then to chip, - goes to chip directly, at least that's how I did it.)Now mount the input jack and toggle switch on the can (line up the headphone jack with it's hole too).

Step 9: Almost There

Finishing touches
If you're like me, you like to use alot of extra wire, so you will want to keep that in the can, I hot glued mine to the inside of the top. Also, if you have an extra switch, like my bass boost, you will want to mount that in a pile of glue to keep it from making contact with the metal of the case (this will cause a disturbance in the force (audio)). You may need to cut away some metal to make the case open and close smoothly. Also, there will be a volume adjuster on the chip, I didn't bother to make this adjustable from the outside of the can, but you can if you want to, you should tweek it until you get the sound you want by adjusting the volume and tone on your guitar and the volume on the chip, some combinations
give you a distortion-like effect that you may like.

Step 10: Break Out the Bubbley

Rejoice, you just saved some money.

Step 11: Farwell Friends

Post some funky fresh ideas for mods to this instructable, comments, suggestions, or your own minty music instructables. Hope this works out for you, hope you could understand my
sketchy instructions even with the lack of pictures, and I hope you enjoyed yourself.