Companies will be able to buy Office 365 Small Business Premium for $12.50 per user per month ($149.99 billed annually).
Microsoft said the Office 365 cloud-based service is designed for organisations with one to 10 employees. Each user gets access to Word, Excel, PowerPoint, OneNote, Outlook, Access, and Publisher and Lync.
"We were going to adopt Office 365 and the lawyers said we could not do it," said Charles Newhouse, head of strategy and design at BAE Systems, speaking during a panel debate at the Business Cloud Summit in London last year.
The service, a rival to Google Docs and Gmail, provides users with a 25GB Outlook mailbox, shared calendar, contact manager, scheduling and task-list tools. Microsoft said it includes 10GB of cloud storage for business. Each user has 500MB of storage space.
A number of businesses have switched from Microsoft Office to Google Docs, mainly due to the lower cost and ease of deployment compared to the on-premise Microsoft office desktop software. In response, Microsoft launched Office 365 last year.
Microsoft is also readying the latest update of its full Office software package, Microsoft Office 2013. Microsoft said anyone purchasing Microsoft Office 2010 from October 19 will qualify to download, for free, one year of Office 365 Home Premium or the equivalent Office 2013 product, when it becomes available.