I have a 2003 Corolla and the check engine light came on. I went to the local Midas shop and they told me I needed a new catalytic converter and it would cost $900. The Dealer wanted 1,500 and Good Year wanted $1,200. I checked a couple of auto part stores and I could buy a catalytic converter for $120. I didn't understand why they were charging so much at the national repair chains. My research said it was a simple install job that would take less than an hour.
I found Acapulco's Mufflers & Auto on they web and they said I could bring my own part and they would install it for $50. They also offered to sell me the part and install it for $180. That the option I took. They had me in and out in forty minutes and did a great job.