Today's 'gifts' are not free, but these magazines are valuable resources that would benefit any nonprofit management team. If your agency budget doesn't allow for at least one affordable subscription, may I recommend a gift from a board member?
The first is my favorite, by far: Nonprofit Quarterly. The affordable subscription price doesn't hurt. What it most attractive, though, is the presentation of timely topics that encourage reflection on issues that matter to nonprofits. Writing style is accessible but respectful of our ability as adults to understand complex issues impacting our organizations.
The second encourages a slightly longer stretch on content, but the presentation is equally rich and accessible. It's also offered at a subscription rate that many nonprofits can manage. Stanford Social Innovation Review focuses content a bit more than NPQ, taking readers a bit further from more familiar management and leadership topics (though it does offer articles and other resources on such issues). But the stretches it fosters generally are in the direction of ideas where exploration and creative thinking would seldom be nonproductive. Another advantage: SSIR makes several of its articles available online for free. Subscription definitely is worthwhile, but the articles archive will give you a chance to test content before committing.
The third comes as a benefit of membership in the Society of Nonprofit Organizations. Nonprofit World presents material in a more basic format, but the topics are very germane to daily nonprofit life. If the magazine isn't attractive enough to commit to membership in the society, the other resources (including access to grant announcements) may be.