I was told the Inner CV Boot was leaking and the entire axle should be replaced

A.Since I've never heard of a CV Boot I'm flying blind here. Does the entire axle assembly (I think there's 2 sides)need to be replaced..estimate was $500..sound fair to you?

A constant velocity (CV) boot is a protective cover, usually made of rubber, plastic, or a similar compound, that provides protection for the CV joints. These joints allow the front axle to manage the torque produced by the drive wheels. They are found in all front-wheel drive vehicles, and there is one boot behind each front wheel. The interior of the CV boot is usually greased or lubricated to protect the CV joint while it's in motion. In most cases, the boot requires maintenance or replacement before the joints because rubber and plastic compounds have a tendency to degrade with age, especially when exposed to heat. It is standard practice to replace the axle when the CV joint is damaged. I don't know if you need both halves or just one with looking at the car so I don't know if the quote was good or not. You can use the repair pal estimator as a check