The remaining eight currently available add-ins for are free: Two of the 10 currently available partner add-ins are paid ones: “Speed Read!” costs $1.99 (as a one-time fee), and the “Dropbox to Outlook Import” subscription costs $1.99 per month. There’s a special page in the Office Store for add-ins. Microsoft’s announcement spends much of its text space and animated screenshots highlighting the company’s partner relationships.