Planning Center People is a free church management system (ChMS) brought to you by Planning Center Online.
You can use PCO People to build lists of the people in your church based on specific criteria. You could build a list of all the parents of middle school students, or everyone in your church who registered for a class last summer and hasn't yet this summer. PCO People is powerful enough to get you the exact information you need.
By integrating your PCO People account with Mailchimp, you'll be able to send an email to the people on those lists.