Four wire O2 sensor source car?

[Trevor Boicey]

Is there a common junkyard car that has a heated
oxygen sensor? I would like to snag one to use for simple
experiments, and paying $50 for one isn't really my bag
either.

  Ideally, I'd like to know a year range and car model that
would be easy picking. Any ideas?

  Also, with heated oxygen sensors, is the heater current
self limiting? Can I just hook it up to 12V switched and it
will be fine, or do I need to control the heating current
in any way? 

  As always, thanks.