Increase SharePoint Online diskspace
The currently available disk space on SharePoint Online is rather limited. Online 250MB per user is provided. During trials you have no possibility to upgrade the amount of available data. However after the trial there is a possibility to buy extra data. This is offered in chuncks of 1 GB at a price level of about 2 euro's.
The trials in Europe right now don't have a possibility at all to upgrade to larger environments. That's because general availability will start from april. Paid subscriptions in western Europe are not possible at the moment.