The black flute is almost worthless, but the white one is a good investment; it can help a lot in the Safari Zone. (If you were allowed to bring pokemon in, one with Sweet Scent would help a lot; but you can't, so a white flute is the next best thing.)

In regards to Secret Base items. a good thing to keep in mind is color. If you are choosing a base made from a tree or grass pile, stay away from green things, like the two largest plants at the flower shop. They don't stand out much. Also, when chosing bricks and desks to place dolls on, make sure that their color does not match that of the doll's color or the color of the base.

One miracle item is the Flat Boards, which, unfortunatly. are not sold until you beat the Elite Four. The largest bases have cracks in the floor, which you need these things to repair; you could build a practical mansion if not for this problem. After you can buy these, keep a look out for the large Bases, and you might find a dream house.

Also, sometimes the Mauville PokeCenter is visited by a Trader. This guy will trade any of your decorations for one of his. Trade him you cheapest decoration for his most expensive one (and if he has a Flat Board, get it.) Unfortunately, he will trade with you only once per visit, and the center has about five other guests (most rather worthless), and they change about once a week, so you never know when he will show up.

- Venusaur