Hey @Bethan I wanted to let you know we just shipped the first pass at supporting other currencies.
To use a different currency for your app, go to Settings -> General
This will change the currency shown in the payment modal however please note it does not affect the
FORMAT_CURRENCY() formula in boundless. We will be getting the appropriate symbol reflected in that formula in the next pass of currency support work.
If you have any questions please feel free to reply here or for faster response use the chat widget in the bottom right corner of Boundless!