Unlimited, you can create as many teams as you like and in any sizes. One common approach is to have one large team for the whole organization and then smaller ones related to activities or daily duties.
A channel is a space where you can share a topic, article or a piece of content with one or several of your team members. The members of the channel can then discuss around it freely through comments and likes. Any user can create a channel and invite its team members.
Simultaneously active users is the amount of users that can be active in the platform during the exact same moment. If you for example have 50 simultaneously active users, it is reasonable to calculate that it would be enough for around 200 - 300 registered users.
Since all organizations needs are very different, we do not have standard prices for Atwork at this point. Contact us, describe your need and we will put together a suitable and attractive quote for you.