Where can I get a cheap o2 sensor

I'm in search of a cheap o2 sensor for 2002 Toyota Tacoma if anyone knows please post the link to the site

 

What's cheap? Rock Auto has the OEM Denso for $100

 

I saw where someone found it on eBay for $25 but I can find the link the guy posted anymore

 

stick with Denso (OEM anyway), do an ebay search, I patiently surfed ebay over a period of weeks and saved considerable when deals showed up, probably the front O2 is probably the bad one, it really takes a beating from the hot engine exhaust, easily the first one to go, just like the Precat, it will go way before the main cat 99% of the time. 304,000, finally had to replace precat, still on original California secondary main cat, and passes smog...

 

Well when I ran the diagnostic on it it threw a catalyst code and a code for the upstream o2 sensor so I'm not sure what all I have to even replace or where I even start

 

You don't want to go cheap. Pay now or pay later.