The largest note in the world, the 500 Billion Dinar Banknote from the Republic of Yugoslavia.
I just had to have one. So, last Friday I ordered it from WSCoin. The online ordering system is a bit weak though and I had difficulty adding multiple items in the basket. Also, I did not immediately get a confirmation email, but did get one when it got processed. The delivery however was fast and I got it this past Tuesday. And they also threw in a million dollar bill! 🙂