It is usually part of the switch unit, (indicators and wipers). Prices can vary, but time spent on the internet might find the cheapest. Care is needed though, there might be different types, as some models had more trip functions and a button on the end of the wiper stalk. Must get the correct one.
Valeo (major car electrical manufacturer) do aftermarket switches, find their catalogue online and ensure you search for the correct one for your car.