You go to Fortree city, and then go into one of the tree houses (keep going until you find the one with two people in desks) and then buy one.
Chat with our AI personalities
Some cool stuff on Pokemon ruby include chairs and desks, posters, dolls, cushions, and mats. Plants and water balloons are also cool stuff you can buy for your Pokemon Ruby.
buy them
You can't. In Ruby, Sapphire, and Emerald you can only buy items, TMs and dolls.
Zangoose does not appear in Pokemon sapphire, but you CAN get it. To get it, you must trade Pokemon with your friend if your friend has Pokemon ruby which is the only game you can get zangoose in. Or you can just buy Pokemon ruby.
You can buy it from the Lilycove Department Store.