It would be great to have this free for individuals - so that they can see if they love it or not. Either make it completely free for them, or free for 2-3 micro-funnels, or free for managing ~250 leads (like highrise).
After that it would be ideal to charge a little ($5/month) for the next 2-3 users, and more for larger teams. Ofcourse, give more features as the team sizes grow.