Players can buy houses from the Town Hall of each major city for the value of 2.000 Gold.
After paying for it, a link should be available from the main city area.
The path to a house is exclusive to the owner of it, but should the owner party up with other players and go inside the house, those players will remember the path until they die or get unconscious.
Houses can be given to groups, be aware that all items inside the house will be accessible to all members of the group and this cannot be undone.
By giving a house to the group all members of it get access to the house and won't forget the path unless they leave the group AND die or get unconscious. Any player that is not part of the group can't access the house unless partying up with current members, even with the link.
To store Items the player can simply drop them on the floor and they won't disappear.
Note: Storing over 50 items causes the 51st and beyond to be buried and therefore disappearing from the items list. Only way to find the item is to pick up everything until it appears. A good way to counteract this is using Large Chests and storing items in them.
Update 09 December 2017: When the character on a FREE account dies, it no longer forgets his house path. You no longer need to save the path of your house as they will be remembered automatically. If you are still missing your house there is a special option in your profile page at the bottom to force the game to give your character his houses back.