If the government behind the Fiat currency becomes insolvent, or acquires extensive debt, their currency may be devalued (relative to other Fiat currencies), their ability to borrow money will be affected (lenders will demand higher interest rates because of the risk), and prices will climb as the currency loses value. At present, Venezuela, Argentina, Zimbabwe, and other countries are suffering due to the inflation they are experiencing. Venezuela is even considering making their own cryptocurrency, the “Petro”, as a solution to their problems.
Some related websites:
What would you do if your money became worthless? – Prosperous Way Down website
A worthless currency – The Economist (Article on Zimbabwe)
11 Times Currency Was Rendered Almost Worthless (and Why) – Ranker
What Happens When Your Money Is Suddenly Worthless? – Cracked (article on India)
Many people invest in Gold and Silver as a “Hedge” against devaluation. This can be done with collectable coins and jewelry, or bullion. Gold and Silver bullion – on eBay.