Thanks all. Got the autozone one for $11. Works great. Unfortunately, as someone quite wisely pointed out, the lack of cap for several days triggered the check engine light. Also in a miraculous and unexplainable turn of events, the driver side power window also stopped working. Anyone care to elaborate on the quantum entanglement between the gas cap and power window mechanism? Heh....
Uh yeah,,,that's easily explainable. The lack of the gas cap in and of itself would not necessarily adversely affect the operation of the power windows. However, in your case, since you turned the engine on and drove the car, you triggered the improper fluctuation of the muffler bearing. The proper synchronization of the muffler bearing with the alternator pump is crucial to the cam regulator timing. When the cam regulator timing is off, it sends variable voltage spikes through the rubber seal circuit. As you know, your windows are in contact with rubber door seals. The voltage spikes which can be in excess of 50K volts travel through the rubber gaskets, through the window glass, then into the electrical circuit. In this case, it looks like your power window switch got defribilated by the voltage spike.
The first place to check is the muffler bearing. Had you upgraded to the chrome muffler bearing this wouldn't have happened. Good luck!