Vending Machine

using System;

namespace _07_Vending_Machine_DONE_
{
    class Program
    {
        static void Main(string[] args)
        {
            string start = "";
            string end = "";

            double strToNumb = 0;
            double change = 0;
            double nutsPrice = 2.0;
            string nuts = "nuts";
            double waterPrice = 0.7;
            string water = "water";
            double crispsPrice = 1.5;
            string crisps = "crisps";
            double sodaPrice = 0.8;
            string soda = "soda";
            double cokePrice = 1.0;
            string coke = "coke";

            while ((start = Console.ReadLine()) != "Start")
            {
                strToNumb = double.Parse(start);

                if (strToNumb == 0.1 || strToNumb == 0.2 || strToNumb == 0.5 || strToNumb == 1 || strToNumb == 2)
                {
                    change += strToNumb;
                }
                else
                {
                    Console.WriteLine($"Cannot accept {strToNumb}");
                }
            }

            while ((end = Console.ReadLine()) != "End")
            {
                if (end == "Nuts" && change >= nutsPrice)
                {
                    end = nuts;
                    change -= nutsPrice;
                    Console.WriteLine($"Purchased {end}");
                }
                else if (end == "Water" && change >= waterPrice)
                {
                    end = water;
                    change -= waterPrice;
                    Console.WriteLine($"Purchased {end}");
                }
                else if (end == "Crisps" && change >= crispsPrice)
                {
                    end = crisps;
                    change -= crispsPrice;
                    Console.WriteLine($"Purchased {end}");
                }
                else if (end == "Soda" && change >= sodaPrice)
                {
                    end = soda;
                    change -= sodaPrice;
                    Console.WriteLine($"Purchased {end}");
                }
                else if (end == "Coke" && change >= cokePrice)
                {
                    end = coke;
                    change -= cokePrice;
                    Console.WriteLine($"Purchased {end}");
                }
                else
                {
                    Console.WriteLine("Invalid product");
                }
            }

            Console.WriteLine($"Change: {change:f2}");
        }
    }
}