What is the difference between a monthly and an hourly gameserver?

A monthly gameserver is a gameserver that will be online 24/7 for the monthly period you've specified. This can be 1 month, 3 months, 6 months or 12 months. An hourly gameserver is a gameserver you will rent by the hour for a maximum period of 24 hours. This option is ideal if you have a clanwar or want to game with friends for a short amount of time.