What Is the Hideout?
The secret hideout or base in "Pokemon Sapphire" is a place you create for your character using the "Secret Power TM," and they are available in those games set in the world of "Hoenn" or "Sinoh." The purpose of the hideout is to provide a personal home for the character, as opposed to the home of the character's mother. They can be decorated with in-game items and can be swapped with other players.
Getting a Hideout
To create a hideout you must train a Pokemon to use the "Secret Power Technical Machine." This is known as "TM43," and you can purchase it in the Slateport market, or find it for free. To find it for free, take Route 111 and go east of the fiery path north of the desert. Speak to the man standing in front of a tree and he will give you the "Secret Power TM." Have one of your Pokemon learn this power. Now, continue normal play of the game while looking for places where a base can be built. Such places include rock walls with indentations, pine trees which will tell you that "vines could be dropped" from them when they are examined, or bushes/grass which tell you that they can be moved when examined. Your Pokemon can use "Secret Power TM" to turn each of these into a base. Each material type (rock, tree, grass) and each location will produce a different base. Save your game before creating a base and see if you like the base you created.
Hideouts and Friends
You can have your friends' bases put in your game world by mixing your Pokemon records. To do this, you must link your GameBoy to a friend's who has a secret base, and you must both go to the second floor of any Pokemon Center and talk to the lady there. Tell her you want to mix records. Your friend's base will now be in your game and vice versa, and you will be able to battle them there.
Items for the Hideout
The primary purpose of hideouts is to provide a place for decorative items in the game. The list of available items includes 35 dolls, 28 ornaments, 18 mats, nine chairs, 10 cushions, nine desks, six plants, 10 posters and wooden boards, all of which are either received as gifts, found or purchased in various locations.