Hey I have a problem with my catalytic converter. Recently I was driving home from work and everything was fine and running as normal and my service engine light comes on out of nowhere. I took it to AutoZone the next day so they could check what it was and they told me my catalytic converter either has a leak, is faulty, or something with it. What are some methods I can take to fix this? I don't want to pay for a new one because I've checked online for some and they're about $500 plus I'll have to pay somebody to put it in for me. If you could find me some for cheaper prices, that would be great. But I'm just wondering if anybody has had similar experiences and what did you guys do?

Thanks!!

btw I have a 2004 sport package coupe G35.