The answer to 'how much does supply line cost' is that the cost of a supply line can vary significantly depending on several factors. In general, supply lines for plumbing fixtures like sinks, toilets, and appliances can range from $5 to $50 or more per line, depending on the material, length, and features.
The main factors that influence the cost of a supply line include the type of material (such as copper, PEX, or stainless steel), the diameter of the line, the length needed, and any special fittings or features. Longer lines or lines with additional features like shut-off valves will typically cost more. The cost can also vary based on your location and the local market rates for plumbing materials and labor.