If you want to convince your friends that money is not an issue, then you can just burn it for real like Walter White. But if you don't really want to destroy your hard-earned cash, this burn trick is perfect for you. It just takes some basic chemistry and a few materials, such as salt, water, alcohol, tongs, and a source of fire. And of course—money.
Pour some alcohol and a splash of water into a bowl. Add a pinch of salt, stir the mix, and drop the dollar into the solution. Make sure the dollar is soaked all the way through and then pull it out with the tongs, letting all the excess drip off. Now, hold the dollar with the tongs or your bare hands (depending on how daring you're feeling) and light away.
Here's a slicker presentation from Steve Spangler:
Once you have perfected the trick, you can up the ante with higher denominations.