Depending on which sensor you buy oxygensensors.com has some of rockauto's prices beat.
For example:
denso 2344625 rear oem o2 sensor $101.98 total oxygensensors.com
denso 2344625 rear oem o2 sensor $103.17 total rockauto.com
I couldnt find a better deal on ebay or anywhere else for that sensor but I did find a great deal on the denso 2344205 front oem o2 sensor on ebay for $74 total. The next closest deal was $86.17 at rockauto.com who had a better price on that sensor than oxygensensors.com at $89.98. So take the time to shop around because it will definitely save you some money.
For example:
denso 2344625 rear oem o2 sensor $101.98 total oxygensensors.com
denso 2344625 rear oem o2 sensor $103.17 total rockauto.com
I couldnt find a better deal on ebay or anywhere else for that sensor but I did find a great deal on the denso 2344205 front oem o2 sensor on ebay for $74 total. The next closest deal was $86.17 at rockauto.com who had a better price on that sensor than oxygensensors.com at $89.98. So take the time to shop around because it will definitely save you some money.
