public interface ISupportPriceInfo 

using Dynamicweb.eCommerce.Common;
using Dynamicweb.eCommerce.International;
using Dynamicweb.eCommerce.Products;
using Dynamicweb.Frontend;

namespace eCommerce.Prices
{

       public class NettoPriceProvider : PriceProvider, ISupportPriceInfo
       {

              public PriceInfo FindPriceInfo(Product Product, double Quantity, string VariantID, Currency Currency, string UnitID, Extranet User)
              {

                     if ((Product.ID.Equals("PROD2"))) {
                           Prices.PriceInfo info = new Prices.PriceInfo();
                           info.Currency = Context.Currency;
                           info.PriceWithoutVAT = 1;
                           info.PriceWithVAT = 1.25;
                           info.VAT = 0.25;
                           info.VATPercent = 25;

                           return info;
                     } else {
                           return null;
                     }

              }
       }
}