There are many different currencies in the world. In order to ensure consistency, certain style codes should be recognized.
Prices should be listed with the currency symbol that travellers will encounter, specifically the local formatting. Travellers should be able to assume that symbols used for multiple currencies (like $, £, €) apply to the local currency.
Unless prefixing is common, don't use a prefix for local currencies. For example:
Use a "." to mark decimals, and use a "," to separate thousands groups.
A billion is a thousand million (American style), not a million million (Commonwealth style).