Where can i get a gas cap that fits so check engine soon light goes off!!

I dont know the code. My gas cap was broken when i got the car so i thought thats why the chek engine was on, according to what i have read.

go to autozone and have them read the code/codes and post them here.no one can help you if no code or codes posted.have them print out your code/codes,it's free.gas cap is one problem,that may make the light come on,but you may have other problem codes also.replace the cap for less than $15.00,have them clear the codes,see if the light comes back on.if it does,get those codes read and post them here.if it don't come back on,problem solved!