http://prepaid-data-sim-card.wikia.com/wiki/Euro1 100 MB high...

http://prepaid-data-sim-card.wikia.com/wiki/Euro1

100 MB high speed volume in 2G and 3G data (up to HSPA+) within the same day until 23:59 UTC+1 (= Central European Time) for 1 € (tax included). If you need more data within a day, another €1 will be debited, which will be valid until 23:59 UTC+1 (= Central European Time) on the same day. If there is no use on a calendar day, there will be no charge as there is no monthly base rate or minimum on the Mundo tariff.

I guess it's 100mb/day for $1. Not sure if the 100mb can rollover to the next day. Not too sure about the sim starter cost & reload denominations. I would assume that users will need to activate roaming prior going to other countries?