How much will it cost to replace oxygen sensor?

Hello, a misfire and a rich running code for bank 1 (P0172) Is not a cause to replace an oxygen sensor. You've got to test the vehicle to find out what is going on. It's possible an oxygen sensor is at fault, but it's one of many possible causes. And, with a misfire present, it adds a bit of concern to that thought process. Plus, the accident part. You can get a price for the sensor by calling some local shops, but I'd suggest having the vehicle checked out properly first before investing money in something you very well may not need.