OrderRepository 9.2.0

NewRepo.cs

var cart = OrderRepository.LoadOrCreate<Cart>(PrincipalInfo.CurrentPrincipal.GetContactId(), Cart.DefaultName).FirstOrDefault();
var price = PriceService.GetDefaultPrice(marketId,
        DateTime.UtcNow,
        new CatalogKey(new Guid(variation.ApplicationId), variation.Code),
        SiteContext.Current.Currency);
            
var lineItem = CreateLineItem(variation, quantity, price.UnitPrice.Amount);
cart.Forms.First().Shipments.First().LineItems.Add(lineItem);
PromotionEngine.Run(cart);
OrderRepository.Save(cart);