CRM software sought for non-profit organization

We are looking for inexpensive software to manage our contact details and emails. Our non-profit association is currently being founded and aims to introduce younger and older people to each other in order to reduce prejudices and achieve better cooperation, so that a “tandem” is created here and there.

The software should be suitable for the following applications

• Management of all contact details for a contact
• Management and processing of inquiries and responses from “grandchildren” by e-mail, such as sending postcards etc.
• We would also like to be able to send personalized emails from the program
• Task management (who does what, when, where) regarding collaboration with different institutions
• Our team works with different operating systems - Mac and Windows
• At best, 10 people should have access, but at least 4 team members