Classes and properties

public class Course
{
    public string Title { get; set; }
    public double Price { get; private set; }

    public Course(string title, double price)
    {
        Title = title;
        Price = price;
    }

    public string Describe() => $"{Title} -- ${Price}";
}

{ get; set; } auto-properties save you from writing manual getter/setter methods for simple fields, while private set keeps Price only settable from inside the class.