We're planning to offer a mass mailing option within Curling I/O as a premium feature. I've always though Mailchimp is more complicated than most clubs require (and their terminology is really confusing).

While awaiting that, if you hit the Mailchimp limit, you should be able to manually export curler lists (by purchase) and import them into other email marketing platforms like Contant Contact etc. However I'm not sure if there's a free option that's comparable to Mailchimp's.