/// <summary>
        /// CTOR - Creates a new MainWindowViewModel Object
        /// </summary>
        public MainWindowViewModel()
        {
            PossibleTickets = Definitions.GetPossibleTickets();
            PossibleMoney   = Definitions.GetPossibleMoney();
            var coinCutoff = 2;

            PossibleCoins = PossibleMoney.Where(m => m <= coinCutoff).ToList();
            PossibleBills = PossibleMoney.Where(m => m > coinCutoff).ToList();

            ShoppingCart     = new ObservableCollection <Ticket>();
            EnteredMoneyBits = new List <decimal>();
        }
        /// <summary>
        /// Calculate Change-List of the differerence between EnteredMoney and the TotalPrice
        /// </summary>
        /// <returns>List decimals representig Money</returns>
        private List <decimal> CalculateChange()
        {
            List <decimal> moneyList = new List <decimal>();

            var total = EnteredMoneyTotal - TotalPrice;

            PossibleMoney.OrderByDescending(x => x).ToList().ForEach(m =>
            {
                while (total >= m)
                {
                    total -= m;
                    moneyList.Add(m);
                }
            });
            return(moneyList);
        }