Ask HN: Low-cost CRM solution for non-profits?

I'm looking to create a simple CRM solution for a non-profit that is tech-savvy, but doesn't want to spend much on the infrastructure (especially not per-user recurring monthly costs, as volunteers should join without much effort or additional cost).

It needs to track mostly the communication: if a volunteer would like to care about a given client, they will be able to look through the recent activities, e-mails, phone call memos, and do what they want to do about it.

One way is to archive all incoming and outgoing mail, and index them in a database, unless the receiver opts out (due to the personal nature of the mail). I've seen zoho mail can archive both incoming and outgoing mail, but other mail host don't do such things, and opting out a certain message is another problem.

It looks like I'll need some administrative UI and workflow, that helps to deal with both processing, re-tagging and searching such communication channels.

Is SugarCRM good for this kind of UI?

How shall we create e-mail and other accounts that allow volunteers to join, yet doesn't add extra cost due their infrequent use? (No issues to subscribe for core member accounts).

Any advice is appreciated.