Want more than 5 private collaborators for free? All you need to do is get your friends on Bitbucket. For each friend you invite who joins Bitbucket, we’ll upgrade your free 5 user personal account by 1 additional user. You can do this up to 3 times for the chance to have 8 private collaborators – all for free.
From your dashboard, send an invitation to anyone by simply entering their email address. When your email invitation is accepted, your 5 user free plan will be upgraded with an additional user.
What about team accounts?
The Bitbucket invitations feature is only available for individual accounts. Team accounts of course are still free for up to 5 users, and $1 / user after that with unlimited private repositories.