I have a 1999 Avalon with 33k on it. The check engine light came on. Car ran fine. Brought it to a local repair shop. They said the 2 O2 sensors were bad. Cost with tax was $900. Each sensor was $353 and labor was $140. He said there are about 3 different type of sensors for the car. Is this about right?

yes they are are right but that seems a little high. Where was your car made ? Is it a california car? air/fuel sensors are more expensive then regular 02 sensors. I dont se any reason why you would have to replace all 3. Usually its just the one by the back firewall that goes bad. It will give off dtc p0135. Heater circuit malfunction bank1 sensor 1

Technically, there can be hundreds of sensors for the car....if your mech said that, hes a retard, and you should find someone else. And the price is fine, 02 sensors are expensive.

The O2 sensors are heated and they cost about $350 each. However, I recently got a letter in the mail from Toyota telling me all emissions-related components had their warranty extended to 150,000 miles. O2 sensors are emissions related parts so if you didn't get such a letter, call Toyota and whine.

But the price for these sensors are correct. Sorry.

http://www.buyoxygensensors.com/

Sensor located in front manifold/exhaust pipebefore catalyst - two required
OEM 4wire Walker $99.99 part 250-24360
OEM 4wire Denso $105.99 part 234-4622
Universal 4wire Walker $59.90 part 250-24200
Downstream sensor, after catalyst
OEM 4wire Walker $119.99 part 250-24107
OEM 4wire Denso $99.99 part 234-4061
Universal 4 Walker $59.90 part 250-24200

The O2 sensors are heated and they cost about $350 each. However, I recently got a letter in the mail from Toyota telling me all emissions-related components had their warranty extended to 150,000 miles. O2 sensors are emissions related parts so if you didn't get such a letter, call Toyota and whine.

But the price for these sensors are correct. Sorry.

Thanks for the info about Toyota extending the warranty on the emissions equipment. Would you please tell me more. I have a '98 Avalon and had a check engine light come on at 39k miles. I took it to my dealer who charged me $85 to tell me that I had to pay $475 to replace the sensor. Please tell me more.

Yeah, you got ripped.
..02 sensor mal-function will turn on the check engine light. If the light wasn't on, then nothing was wrong.
..50 bucks at an auto parts store for a code reader is a better investment.
..And even if the light was on and the 02 was malfunctioning, big deal !
Unless you live in an emission control area(colorado USA), having a check engine light on is no big deal either. You can drive with that little light on as long as you want. It can double as a map reader light if you want it to.

Get a new mechanic. An honest one. Ask a friend.