10mm 15Kmcd Slow Flashing MultiColor RGB LED-I got mine from ebay. They cost around 50 cents US Dollars depending on the quantity. I bought a couple hundred and got a discount (about 15 cents) from this ebay store.
. You can either get slow flashing or fast flashing. They don't actually flash, they just change color.
Proper resistor(s) for your LED
9volt battery and snap
Jar- I found one that is diffused a little
Toggle Switch- I bought a one a radioshackTools
Drill and bit that matches the size of the toggle switch.