Coin of the realm in different multiples. Old silver dollarsand bars of silver, gold coins from 1/25 oz up to 5oz, they are not fiat money if they are pure silver or pure gold. A 1 oz silver coin made in Ancient Roman times is still 1oz silver today and has the same purchasing power. Same with any currency in existence. Problem is the premium to buy new, so buy privately rather than from a mint and save large. 5% premium is the max you want to pay.