When you are charging your client using a Checkout Page, any currency we support in the builder. However, certain currencies are treated differently than others.
We have fixed prices for the currencies supported inside the builder, which are currently USD, CAD, AUD, GBP, and EUR. If you your Stripe account is set to one of those currencies, we will fix the price at the current conversion rates and StickyApps will take on the risk of currency fluctuation.
You can change the currency used when you create a checkout page. Check out this article for more information on how to setup your currency: How do I Create a Checkout Page?
If you want to charge a small business with any other currency, you will need to set your currency on the checkout page to be USD, and the card holder's issuing bank will convert from USD to their local currency at the time of the charge, based on conversion rates at the time. So, if it's not a currency we currently support in the builder, the price can fluctuate slightly based on changes in conversion rate.