Auto Parts: heated o2 sensor Hyundai tucson, frequent flyer program, hyundai tucson

Question
I need a heated 02 sensor (rear) for my 07 Hyundai Tucson. I called a autoparts store they wanted 200 dollars. The dealer wanted 350. I found it online for 68 with the plug. Why do the prices vary so much? How long can I wait to fix it if the light just came on? Would it be safe to buy this part used from a salvage yard? Oh I should mention my car has to many miles to be covred under warranty thanks to being military and travailing cross country

Answer
    I assume that you at least tried to get the dealer to warranty it.  Emissions parts are warranted for 50,000 miles, and Hyundai has an even longer warranty.  If you're driving more than 25,000 miles  per year, then you need to look into a frequent flyer program.  When you say $68 with the plug, does that mean the plug is installed or you have to do it yourself?  There is really no reason not to use a universal oxygen sensor with a spliced-on plug, but you have to be extra careful that the connections are very good.  The voltage produced by the sensor is pretty low, and DC voltage drops dramatically at low levels with any sort of resistance.  I looked at the prices of these things and you're right, they are all over the place.  I can't offer any advice on that subject except that, in my almost thirty years in the parts business, I've found that you generally do get what you pay for.