beck400 Depending on your location, you can change your payment method before confirming using Epoch to Sofort, PaySafeCard too.
AMEX is not accepted by any of our payment brokers.
Pre-paid cards are also accepted by both Epoch and Verotel; Some pre-paid card issuers/banks require you to ask them to allow the payment though.
You can pay per item without and with balance. Doing many small purchases in a small amount of time can trigger Epoch's, VISA etc fraud prevention though. If you know you're gonna buy several items it's best to top-up your balance.