Materials LED- I used a 10mm RGB self cycling LED. 15-50 Cents. You can take an LED pretty much any old electronic device or buy them online. Radio shack sells them for an arm and a leg. Coin Cell Battery- I used the CR2032. Very Common. You can get them at radio shack or online. Even Big Grocery Stores have them. They cost any where from 20 cents a piece online to close to $5 dollars at radioshack. Electrical tape- About 5cm. You could even use duct tape. Shell- Any shell that is big enough to fit an LED in.