Hoplix gives you the possibility to send out Newsletters to the users of the store. 

Select the campaign, enter the text and send the newsletter to all your customers. 

It is free. 

You can send only ONE email per month, but you decide when in the schedule section. All you have to do is write down what you want to communicate to your customers and decide whether to send it at the time or postpone it. 

The newsletter can be found in: Your Account > Store > Messages