Please read this post for more information:
http://www.knowhowinaction.com/2010/09/how-to-get-mastercard-prepaid-card.html
Up-to-date information on Ryanair booking fee: No credit card fee applies when paying with a debit card or SEPA bank transfer (Germany only).
Bookings paid for by PayPal, American Express, credit card or a Mastercard Prepaid card will incur a fee of 2% of the total transaction value.
