Need to collaborate in "Real Time".. with your team?? Google ... direct support in Google Drive... Its impressive !
The pricing models:
Free- 3 boards, 100MB of storage - basic, although very usable
Premium - $10 - unlimited boards, 3GB storage ...
Team - $10/user/Month- unlimited boards, 3GB storage ...few extra features
Check it out !!
Any questions? let me know