So when I start my car, it makes a sound as if my muffler was going. There's also a nasty carbon monoxide smell. It makes me think that my exhaust has a hole in it and needs to be fixed. I was able to get it "patched" last year however I feel as though it's not gonna be that easy. Anyone know approximately it would cost to fix the exhaust completely.

Thanks

 

Because different parts of the country charge different rates, it might be a good idea if you called a few places like midas, pep boys, and other shops in your area to get an idea what they charge and just what that includes. As you are probably aware winter time driving with all the windows closed and having a chance for exhaust fumes to enter the vehicle is not the best of conditions. Depending on just what needs to be replaced, you cold do your own work if you had the tools and facilities. Most of the time the entire system from the catalytic converter(s) back toward the rear wind up getting replaced.
Before jumping the gun it is best to get some idea of just what is leaking.