public double GetCountryVAT()

class MyPage : System.Web.UI.Page
{
    private Dynamicweb.eCommerce.Products.Product product;

    private void Page_Load(System.Object sender, System.EventArgs e)
    {
        product = (Dynamicweb.eCommerce.Products.Product)Session["Ecom.Backend.Product"];
    }

    public OrderLine SetUnitPrice(OrderLine orderLine, double amount)
    {
        string originalPriceInDBSetting = Base.GetGs("/Globalsettings/Ecom/Price/PricesInDbIncludesVAT");
        bool isPricesWithVat = Base.ChkBoolean(originalPriceInDBSetting);

        double systemVat = 0.0;
        double discountPrice = 0.0;

        if (isPricesWithVat)
        {
            discountPrice = product.Price.PriceWithVAT / 100 * amount;
        }
        else
        {
            discountPrice = product.Price.PriceWithoutVAT / 100 * amount;
        }

        if (double.TryParse(Base.GetGs("/Globalsettings/Ecom/Price/PricesInDbVAT"), out systemVat))
        {
            discountPrice *= 1 + (systemVat / 100.0);
        }

        //Remove country VAT
        discountPrice /= 1 + (new Dynamicweb.eCommerce.Prices.PriceCalculated().GetCountryVAT() / 100.0);
        //Set unit price
        orderLine.SetUnitPrice(discountPrice);
        return orderLine;
    }
}