Money - Wikipedia
In a collapse of the system, there will be multiple phases, with the first phase being the “crunch”, as discussed in James Rawles ‘ book Patriots . The crunch is the period of time directly preceding a collapse and the collapse itself.
In monetary economics , fiat money is an intrinsically valueless object or record that is widely accepted as a means of payment.  [ not in citation given ] In some micro-founded models of money, fiat money is created internally in a community making feasible trades that would not otherwise be possible, either because producers and consumers may not anonymously write IOUs , or because of physical constraints.  
Fiat money is a currency without intrinsic value established as money , often by government regulation. It has an assigned value only because the government ...
The word "money" is believed to originate from a temple of Juno , on Capitoline , one of Rome's seven hills. In the ancient world Juno was often associated with money. The temple of Juno Moneta at Rome was the place where the mint of Ancient Rome was located.  The name "Juno" may derive from the Etruscan goddess Uni (which means "the one", "unique", "unit", "union", "united") and "Moneta" either from the Latin word "monere" (remind, warn, or instruct) or the Greek word "moneres" (alone, unique).
When I asked a PayPal spokesperson if the company views Facebook Messenger payments as a “competitor,” they carefully avoided that word but eventually admitted “it does have similar technology and does a similar thing to what Venmo does.” While Venmo makes transfers with most debit cards free, Facebook’s free service will undercut PayPal’s percent plus $ fee per transaction from debit cards.
The hard parts are 1) the research and planning stage, 2) the creation of high-value content for your site (and social media), 3) traffic-building, and 4) monetization (converting visitors into income).