Which Transmission Range Sensor part / repair at dealer or elsewhere?
 

My '08 Mazda3 will not start in park, only neutral. From what I have read it seems it is the Transmission Range Sensor (I believe also called Neutral Safety Switch, unless they are different components...?). Is there a specific OEM part that I need to get for the car, or can I just buy any TRS at a parts store?

Should I avoid getting it repaired at the dealer? They wanted something like $150 just to analyze the problem, aside from parts and labor, so I am not so sure about going in there just for the labor either.