Vodafone Spain offers double data allowance from July 15th to August 31st for a one time charge of 2€ for its prepaid offers yu, Vodafone Internacional and Vodafone in Spain. For example 2 GB data for 17€ or 3.2 GB for 22€. Use *346# to activate the double data offer.
http://www.vodafone.es/conocenos/es/...sfrutaran-del/