public class PricingMotor_cls {
	public Double cost;
	public OrderItems[] orderItems;

//Wrapper for OrderItem
	public class OrderItems {

		public Integer quantity;
		public CashAmounts creditAmounts;
	}

	//Wrapper CashAmounts 
	public class CashAmounts {
		public Double totalPrice;
		public OrderConditions[] orderConditions;
	}
        //Wrapper OrderConditions 
        public class OrderConditions {
		public String conditionType;
		public Decimal amount;
	}

}

List<ISSM_DeserializePricingMotor_cls.OrderItems> abc = new ISSM_DeserializePricingMotor_cls.OrderItems[1];
abc[0].quantity = 1;