Here are the codes for the V2 shop:
SHOP CODES
1. ABBA ACBA = cake
2. BCAB ACBC = steak
3. CBAC CABC = cuckoo clock
4. AABB CACB = RC Car2
5. CACA BABC = stuffed animal
6. ACBB BACC = hairgel
7. BCBC CABA = love potion (honey)
As for buying a battery you can usually find them at most stores like Wal-Mart in the watch battery section. The battery you will be looking for is a CR2032 they are very common and easy to find.
:.Chloe.: