Zotero Now Offers 100 MB of Free Storage for PDFs, Images, etc.

Zotero now offers 100 mb of cloud-based storage for PDFs, images, screenshots, and other files free of charge. Additional storage space can be purchased if needed.

For more information check Zotero's storage faq.

If you are not already familiar with it, Zotero is a free bibliographic management tool for researchers.