Trade by barter is the system where you give what you have to get what you need but the Global Economic system has improved greatly and moved away from this system to a more advanced form of economic transactions to the point that we now have cashless transactions taking place all around the world via Credit Card and other systems...
But you must know that what keeps people coming back to you is because of the service or products that you offer to them which meets their needs... hence without you being able to offer anything you will most likely not be patronised for anything.
Even when people are paid to patronise you they will end up being disappointed because you have nothing to offer them.
However It is your discoverable and developed differences which keeps people [clients] coming back to patronise you.
So my point is that , It will be of much benefit to you when you view your destiny and the socio necessary impact you need to make via the Trade By Barter kind of system:
Ask Yourself//-- What do I have to offer in exchange for the things that I need.. Its called the ''Unique Selling Point'' your marketable difference that will put wealth n your pocket.
If everything you have was taken from you , your factory got burnt and you needed to start all over again! what are the things you have that you can start trading with again?
Know what this is and keep developing it to the point that you become a reference for your competency.