talk to the emission testing authority with the state and have them send you where you can get rechecked without discussion under their rules. if the cost exceeds a waiver it is customary they will ask you to spend up to that amount attempting to correct any failed part(s) that directly improve the readings. They keep stringent rules and guidelines for this. If you involve them immediately they can save you some time and trouble. They also can Q&A over the phone, helping you realize any choices you may have.

Why are you being charged for an emission test? They are free and the cost is covered as part of the license plate fee. Go somewhere else!

depend how old the convertor is, it can go bad within a years time. even if last year it was ok. if you don't trust him then take it to another shop to have it looked at.

CAT's wear out, yours has worn out so you need a new one, it is as simple as that.

I went to get a smog check for a car that was given to me by my uncle today and it failed. The auto mechanic asked me if I ever modified my catalytic converter and I said no. He wants me to pay 360$ to replace it and he also charged me $59.75 for the smog check inspection. I told him that I didn't have the money to replace the catalytic converter yet so he gave me 15 days to get it. The thing is I went home and found the smog check paperwork (from the same shop) from 2013 last year and it passed with no problems for some reason. I am new to all of this, I hope he's honest and isn't trying to rip me off since I don't know much about cars. Thanks for any help.