While scrounging through the local "Five Below" today, I found flickering tea candle LED lights for $1 each! They were near the incense and lava lamp-style lamps.
These are great for randomly flickering lights (fires, etc.) and at $1 each, how can you go wrong?
Here is a page showing how to hack the lights to run high-powered LEDs; the same principles may work to use blue/green/etc. LEDs, though I haven't yet tried it (but I will... oh yes, I will

http://www.johnnyspage.com/otakuFlicker ... kuHack.htm
I'm going to be using these in a 1/48 scale haunted house I'm building for display on Halloween this year

Jeff