SimpleTix can work with any currency.
The only limitations are set by the payment gateway you choose. For example, see what countries PayPal is compatible with.
Select a payment gateway that is right for your currency; and then simply choose the appropriate cultural setting to display that currency on you SimpleTix site. To change your default language go to: Settings & Options > Store Settings. From here you can set this.
Examples: Notice that both the Date/Time and Currency are both formatted to match the country.