I've completed the first four levels, but I can't seem to access any more of the overworld. I've bought every individual item I can find under the current maximum of 250 rupees. (Bait, Shield, Bow, Potion, Wand, Magic Book, and the 240-rupee bomb/arrow upgrades)
There are two areas north of Level 4 where it appears I need Super Bombs, but I can't find a Super Bomb Shop. I've found the shop that sells the Hammer, Power Bracelet, and Mirror Shield, but they all cost more than 250 rupees. I also cannot buy the Flute yet because it costs 350 rupees.
I've found the Magical Sword, but with only 7 hearts, I'm nowhere close to getting it.
So where do I upgrade my wallet to carry more Rupees? And where is the Super Bomb Shop? I presume having the Hammer, Flute, and/or Power Bracelet as well as the Super Bombs will help me find Levels 5 and up?