my check engine light is on got it checked and said it was a oxygen sensor, got

Yes..if your o2 sensor is bad, your check engine light will come on. Also, you make sure what one is bad. I believe all cars have a top o2 sensor on manifold and one down stream by the donut..

the engine code you have does not tell you to replace the 02 sensor.that is maybe ONE of the possible causes.maybe you have a P0135 or P0141 engine cod, etc.but it just don't mean,to go and start buying parts that you may or may not need.unless you had a good mechanic with a real scan tool,(not a code reader from a parts house),then it's called guessing,and it may fix it and may not.and yes it will cost money to hook up to one of these scan tools with live data,but it takes out all the guessing,before you have six or eight hundred dollars tied up in it guessing at it.hope this make sense.