tx.cs

public class Report
{
    public string Name { get; set; }
    public List<Sale> Sales { get; set; } = new List<Sale>();
}

public class Sale
{
    public Customer Customer { get; set; }        
    public Product Product { get; set; }
}

public class Product
{
    public string Name { get; set; }
    public decimal Price { get; set; }
}

public class Customer
{
    public string Name { get; set; }
    public int Id { get; set; }
    public string Street  { get; set; }
    public string City { get; set; }
    public int Zip { get; set; }
}