Please note that the invoice will include Hungarian VAT (27%), regardless of your billing country or company registration. This is due to the place-of-supply rules under the EU VAT Directive (2006/112/EC), which specify that VAT for admission to events — such as conferences — is charged in the country where the event physically takes place.
Payments are processed through PayPal. You may pay using an existing PayPal account, or any major credit card / debit card. If you have an existing PayPal please use it.