Speaking of killing you, as we are using water and electricity here, please be supper-duper cautious. I can't be held responsible for burned fingers, house fires, dead cats or any combination thereof. Please use some common sense!
This is a decent project that should cost you little or no money, depending on what you have laying around the house. The idea is to use electricity and salt water to etch an image into the top of an altoids tin. The same process can be used to actually cut the image all the way through if allowed to go long enough. I'll explain the principles behind this as we go along.
First things first, Project materials and cost:
1 Altoids can, or similar metal canister - $0 (I'm using garbage here...)
1 spare DC power supply brick. 5v or greater. Preferably a decent amperage. I use a 12v 1A supply. it really seems to make no difference beyond how long the etch will take - $0
Old PC case fan, light bulb.. something that will run on the current from the power supply. This is used to limit the amount of current being transmitted, as you don't want to burn out the power supply. - 0$
1 PLASTIC bowl or pan. Never NEVER use a metal pan of any kind. - 0$
About half a cup of salt. - 0$
A couple of bolts and some heavy copper wire - optional 0$
Plastic packing tape (I use clear.. don't have to I suppose.). Not masking tape. It has to stand up to salt water - 0$ I steal mine from my day job.
Sandpaper, or green scrubby. -0$ I used the scrubby from my kitchen sink. Don't tell the girlfriend.
Razor blade or knife. I highly recommend an Exact-o or similar, although I did this with a straight "utility" style blade.