Trade Comissions

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _08.Trade_Comissions
{
    class TradeComissions
    {
        static void Main(string[] args)
        {
            string town = Console.ReadLine().ToLower();
            double sales = double.Parse(Console.ReadLine());
            double comission = 0;
            bool isTown = town == "sofia" || town == "varna" || town == "plovdiv";

            if (!isTown)
            {
                Console.WriteLine("error");
            }

            if (town == "sofia")
            {
                if (sales >=0 && sales <=500)
                {
                    comission = 0.05;
                    Console.WriteLine("{0:f2}",sales*comission);
                }
                else if (sales > 500 && sales <= 1000)
                {
                    comission = 0.07;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 1000 && sales <= 10000)
                {
                    comission = 0.08;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 10000)
                {
                    comission = 0.12;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else
                {
                    Console.WriteLine("error");
                }

            }
            else if (town == "varna")
            {
                if (sales >= 0 && sales <= 500)
                {
                    comission = 0.045;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 500 && sales <= 1000)
                {
                    comission = 0.075;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 1000 && sales <= 10000)
                {
                    comission = 0.1;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales >10000)
                {
                    comission = 0.13;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else
                {
                    Console.WriteLine("error");
                }
            }
            else if (town == "plovdiv")
            {
                if (sales >= 0 && sales <= 500)
                {
                    comission = 0.055;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 500 && sales <= 1000)
                {
                    comission = 0.08;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 1000 && sales <= 10000)
                {
                    comission = 0.12;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else if (sales > 10000)
                {
                    comission = 0.145;
                    Console.WriteLine("{0:f2}", sales * comission);
                }
                else
                {
                    Console.WriteLine("error");
                }
            }
        }
    }
}