Best CRM for Club website? Using gravityforms to collect data?

Hi,

For a Martial Arts Club I'm looking for an easy and hopefully free CRM plugin/service that can handle a simple newsletter send every once a months and to make it easy to see who has paid and who not in a list format.

I don't need all the sales, marketing and other stuff most of the CRM systems have.

Any suggestion to an easy system that integrates with GravityForms?

I used woocommerce customer relationship manager plugin on a client website and really like that one. It's not free but only $55 and can do what you want.

I believe it integrates with gravity forms. My client uses GF and upon form submit their contact info gets inserted as a user in CRM.