Why Nations Can't Just Print Infinite Money: The Mechanics of Inflation
Printing money increases the aggregate supply of currency without increasing the real output of goods and services; as more money chases the same fixed quantity of items, prices bid upward, causing the purchasing power of each unit of currency to drop.
Imagine an auction where 10 people bid on 10 freshly baked pizzas. Everyone has $10 in their wallet, so pizzas sell for around $10. If someone drops $1,000 in cash into everyone's wallet, there are still only 10 pizzas. The bids instantly jump to $1,000 per pizza—nobody got more food, the dollars just became worth less.