Removal of objects in obj-c

Question

I'm using ARC.

I'm got a button that runs this code, to create an object (an SPPrite object using the Sparrow Framework)

 SKMarket *market = [[SKMarket alloc] initWithScrollContainer:scrollContainer];

Inside that market item I have a "close" button, which runs this code...

[self removeAllMarketButtons];

    [closeMarketButton removeFromParent];

    scrollContainer2.visible = YES;

    [self removeFromParent];

And that does indeed remove the market object, what I don't understand though is what happens when I click the button to set up market again, and I run this line again...

 SKMarket *market = [[SKMarket alloc] initWithScrollContainer:scrollContainer];

I'm a AS3, in AS3 in my close button I would do all the above, but I would also do something like...

parent.market = null;

So when I run the code that sets up the market it's all start fresh,

1. what happens though in that situation in obj-c?
2. Is the item still there even though it's not visible?
3. Is it better to start with a fresh market object? or..
4. If the old market object is still there somehow re-fresh it with new assets again?