public static decimal GetFinalPrice(Order order)
{
List <decimal> rebateprices = PromotionManager.GetActivePromotions()
.Select(promo => PromotionManager.GetTotalRebatePrice(order, promo))
.ToList();
decimal origprice = order.Products.Sum(x => x.UnitPrice);
decimal rebateprice = rebateprices.Sum();
return(origprice - rebateprice);
}