implement a fluent builder for basket in csharp

main.cs
public class BasketBuilder
{
    private readonly Basket _basket;

    public BasketBuilder()
    {
        _basket = new Basket();
    }

    public BasketBuilder WithItem(string name, decimal price, int quantity = 1)
    {
        _basket.Add(new BasketItem(name, price, quantity));
        return this;
    }

    public BasketBuilder WithDiscount(decimal discountAmount)
    {
        _basket.ApplyDiscount(discountAmount);
        return this;
    }

    public Basket Build()
    {
        return _basket;
    }
}

public class BasketItem
{
    public string Name { get; set; }
    public decimal Price { get; set; }
    public int Quantity { get; set; }

    public BasketItem(string name, decimal price, int quantity)
    {
        Name = name;
        Price = price;
        Quantity = quantity;
    }
}

public class Basket
{
    private List<BasketItem> _items;

    public decimal TotalPrice => _items.Sum(item => item.Price * item.Quantity);

    public decimal TotalDiscount { get; private set; }

    public decimal FinalPrice => TotalPrice - TotalDiscount;

    public Basket()
    {
        _items = new List<BasketItem>();
    }

    public void Add(BasketItem item)
    {
        _items.Add(item);
    }

    public void ApplyDiscount(decimal discountAmount)
    {
        TotalDiscount += discountAmount;
    }

    public IEnumerable<BasketItem> GetItems()
    {
        return _items.AsEnumerable();
    }
}
1430 chars
72 lines

main.cs
var basket = new BasketBuilder()
    .WithItem("Apples", 0.5m, 2)
    .WithItem("Oranges", 0.75m)
    .WithDiscount(0.1m)
    .Build();
136 chars
6 lines