The price of a professional sound level meter can vary depending on several factors, such as its level of accuracy and features. A high-end Class 1 SLM, which offers the most accurate readings and a wide range of features, can cost anywhere from $3000 to $9000. The most expensive Class 1 meters can cost upwards of $6000 to $9000. Mid-range Class 1 meters, which offer good accuracy and a limited set of features, can cost between $3000 to $6000. If you’re looking for a more affordable option, a Class 2 sound level meter, which is less accurate but still suitable for many applications, can be purchased for a price range of $1500 to $2000. Ultimately, the price you’ll pay will depend on your specific needs and the level of accuracy and features required for your application.