The answer to 'average cost of shut-off valve' is that the cost can vary widely depending on several factors. Typically, the average range for a basic shut-off valve replacement is between $100 to $300, including labor and materials. However, the actual cost will depend on the type of valve, the location, and the complexity of the installation.
Some key factors that influence the cost of a shut-off valve include the material (brass, PVC, or metal), the size of the valve, the accessibility of the plumbing, and whether any additional repairs or modifications are needed during the installation process. Valves in hard-to-reach areas or that require more extensive work will generally cost more. It's essential to get local quotes from licensed plumbers to get an accurate estimate for your specific situation.