Logisys 12" Cold Cathode Dual Kit ~ $6
Two cathodes for $6 is unbeatable. They used to be for around $3 for a dual kit, but considering the fact that some stores around me sell 'em for $15, six bucks seems very attractive.
Here's my PC with the logisys green cathodes:
Of course they aren't as bright, but that's what you get for a 5 second exposure.