Vending Machine 2nd option

using System;
using System.Globalization;


public class Program
{
	public static void Main()
	{
		decimal sum =0;

		while (true)
		{
			string money = Console.ReadLine();

			if (money == "Start")
			{
				break;
			}
			decimal coins = decimal.Parse(money);

			if (coins == 0.1m || coins==0.2m || coins==0.5m || coins==1.0m || coins==2.0m)
			{
				sum += coins;
			}
			else
			{
				Console.WriteLine("Cannot accept {0}",coins);
			}
		}

		while (true)
		{
			string product = Console.ReadLine().ToLower();

			if (product == "end")
			{
				break;
			}

			if (product == "nuts")
			{
				if (sum <2.0m)
				{
					Console.WriteLine("Sorry, not enough money");

				}
				else
				{
				   sum -=2.0m;
				   Console.WriteLine("Purchased {0}",product);
				}
			}
			else if (product == "water")
			{
				if (sum <0.7m)
				{
					Console.WriteLine("Sorry, not enough money");

				}
				else
				{
				    sum -= 0.7m;
				    Console.WriteLine("Purchased {0}",product);
				}
			}
			else if (product == "crisps")
			{
				if (sum < 1.5m)
				{
					Console.WriteLine("Sorry, not enough money");

				}
				else
				{
				   sum -= 1.5m;
				   Console.WriteLine("Purchased {0}",product);
				}
			}
			else if (product == "soda")
			{
				if (sum < 0.8m)
				{
					Console.WriteLine("Sorry, not enough money");

				}
				else
				{
				   sum -= 0.8m;
				   Console.WriteLine("Purchased {0}",product);
				}
			}
			else if (product == "coke")
			{
				if (sum < 1.0m)
				{
					Console.WriteLine("Sorry, not enough money");

				}
				else
				{
				   sum-=1.0m;
				   Console.WriteLine("Purchased {0}",product);
				}
			}
			else
			{
				Console.WriteLine("Invalid product");
			}
		}
		Console.WriteLine("Change: {0:f2}",sum);

	}
}