If your car is leaking exhaust, it's important to get it fixed as soon as possible. Exhaust leaks can be dangerous because they allow deadly carbon monoxide gas to enter the passenger compartment of your car. Carbon monoxide is odorless and colorless, so you might not even know you're being poisoned by it.
The cost to weld an exhaust leak will depend on the severity of the leak and where it's located. A small leak in a easily accessible spot may only cost a few hundred dollars to fix, while a more serious leak that requires disassembling part of the engine could cost upwards of $1,000.