One of the oddities of the Zelda franchise is its currency system — Link runs into strangers homes to loot their chests and smash their pots for money, and he can even accumulate wealth when chopping up grass in the wilds. We've tried cutting grass ourselves in the hopes that money will simply appear where the overgrowth once was, but it's a video game quirk sadly lacking in real life.
In any case, accumulating rupees — and larger purses in which to carry them — has been an important part of the franchise. Picking up ammo, expansions and useful tools from shops is a key part of the overall adventure, yet producer Eiji Aonuma has spoken to Official Nintendo Magazine and suggested that the importance of collecting money is even greater than normal in upcoming 3DS release The Legend of Zelda: A Link Between Worlds.
Collecting rupees, the currency of the Zelda world, will be very important in this game. You might think that was the case with all the past games too, but I must say that this time it will be more important than ever and you will need to collect a great deal of them.
...Shops in the past Zelda games sold things that would run out once you use them like arrows and bombs, items that needed replenishing. They have never sold an item that doesn't go away after each use like the boomerang or the hookshot.
It seems that some key items may no longer be picked up by defeating certain bosses or navigating to key points in dungeons, but may actually simply be items for sale in stores. Or perhaps, with the Nabbit-esque character in the store screenshot above, items will be stolen from you and you'll have to retrieve them with cold, hard rupees. We'll have to wait and see.
So don't forget, if you see a pot or some grass, have at it.