In old times, people were exchanging goods, today we barter with paper money issued by the government. Whether people realize it or not, the bartering system is still alive and well. We do it every single day, when we go to the grocery store, the gas station, and when we pay the rent.
In a SHTF-type of scenario, paper money is completely and utterly useless. If you think that having a pig pile of supply will save you, think twice! You’ll still need to be able to barter with other survivors to get the supplies you and to survive.