There are many different types of shopping opportunities here!
What to do in Ikebukuro!
If you are into Otome or genres similar. Then visit the 9 story building Animate!
Nearby Animate is Sunshine City (shopping), where an aquarium is located within the complex. See sea lions, penguins, and more!
Inside Sunshine city complex is also a bunch of shopping you can do, visit J-world, go into the Pokemon Center, and more! You may be able to catch a J-Pop group perform.
Kurand Sake Market
Pay a fee and enter into a Sake market where you get unlimited access to different types of SAKE!
Konica Minolta Planetarium
Luxuriously chill at a planetarium also located in Sunshine City! The Planetarium hosts a different screening at different times. Check on their website to reserve or look up the schedule (Japanese only).
Drink and eat with Penguins! Book online on their website (English available)!
Shopping in Ikebukuro is pretty cheap too. There are a bunch of department stores the moment you exit the JR Station. Take a look around!