Prices are set separately for each currency (GBP, USD and EUR) at our online shop, and they are reviewed periodically. It means in a case of rapid currency exchange rate fluctuations our prices may not be adequate to the current official exchange rates.
If you notice your USD price is way higher in comparison to the EUR price based on official EUR to USD exchange rate, then switch to EUR currency during the checkout. If you do so, your credit card or bank account issuer will perform the conversion with a rate most close to the official.