From Bulbapedia, the community-driven Pokémon encyclopedia.
The Veilstone Department Store (Japanese: トバリデパート Tobari Department Store) is located in Veilstone City, west of the Pokémon Center. This department store is similar to the Celadon Department Store, the Goldenrod Department Store, the Lilycove Department Store, and Shopping Mall Nine. The store offers a wide variety of items on its five floors. A sign outside reads:
B1F: Contest Tools
This basement is a new addition in Platinum Version. There are three stalls to buy items from. One deals with Poffins for Contest use, one for Berries, and the other with Lava Cookies. Poffins sold here are level 32 and have a smoothness rating of 20. There is also a lady that sells Rage Candy Bars, but claims she is all out. Professor Rowan can occasionally be found here, hoping to buy some Rage Candy Bars.
1F: Trainers' Zone
When players enter the Dept. Store, there is a lady to the left of the entrance who will give away a mask to be put in the Fashion Case. The mask will match the starter Pokémon of Rowan's assistant (the player character not chosen). The people at the reception counter sell items commonly found in Poké Marts.
2F: Battle Collection
On this floor, a man behind the counter will give away the Counter Pokétch app. Battle items and vitamins are sold here as well.
3F: TM Corner
TMs are sold here.
4F: Poké Dolls & Goods
Secret Base decorations are sold here.
5F: Rooftop Plaza
A man will give away a Sticky Barb here. Inexpensive healing items can be bought on this floor, too.