For hosting common files it's ok. Also it is on Android too do, great to transfer files between your Windows and your phone. But if you want better security you have to subscribe a monthly offer.
Dropbox - Online Sync and File Sharing
Birdly - Birdly is an expense management and expense report solution for SMBs.
Google Drive - Access and sync your files anywhere
Expensify - Import expenses directly from a credit card to create free expense reports quickly. Approve reports online and reimburse directly to a checking account with one click.
Mega - Secure File Storage and collaboration
Fyle - Track expenses across devices on-the-go and maintain a central repository. With custom approval flows, automatic policy violation detection and an automated audit trail, be audit-ready at all times!