Monetary inflation Prices rise when a government issues too much money (see The Quantity Theory of Money)
Cost inflation an increase in the general price level originating in the production market. When companies’ costs go up, they need to increase prices to maintain their profit margins. Increased costs can include things like: wages, taxes, or increased costs of imports (oil).
Demand inflation if demand grows faster than supply, then prices will increase. This usually occurs in growing economies.