In order to format money with the given currency, you should use one of the money filter. All of the int values for a price are times 100, the filter will set a decimal point at the right position and add a currency symbol at the correct position.
This filter will output a given price value (which is times 100) with the according currency symbol. All prices (and thus currency) depends on the country of the shop user.
Example:
{{ 399 | money }}
Output:
$3.99 (When the users origin is in the USA)
3,99 € (When the users origin is in Germany)
Same as the money filter.
Similar to the money filter, but just outputs the price as a number with two decimal places (without any currency symbol).
Example:
{{ 399 | money_without_currency }}
Output:
3.99