There's 20 nickels to the dollar, so I come up with 20,000,000,000 nickels.
At 5 grams each, that's 100 billion grams = 220,462,442 pounds
A 2006 article claims that there are approximately 20bn nickels in circulation, so the Apple payment would require every US nickel in the world. Since I have 3 in my pocket, Samsung will be short of the total.
I have seen other sources that claim there are as many as 25bn nickles in circulation.
More:
http://www.theguardian.com/technology/blog/2012/aug/29/apple-samsung-trucks-nickels-fake