1. Send Bulk Emails on Monthly Rental Basis.
Take the service of any email service provider which can provide you platform to send mail through them and for using their service you need to pay them monthly rental based on per email sent or per subscriber.
Pros: In this case you do not have to worry about blacklisting of the email server or IPs in case of spamming, but they can block you if something happen like this.
Cons: The charges are very high. (more then $100/month for an avg. plan)
2. Setup Bulk Email Server for Your Own,
The second solution is the best which I refer to most the people since it is less costly and only charge one time setup fee if you running a start up or a small business.
You have to setup SMTP email server by any email server setup solution provider company for your own and send emails quantity as much as you want and you do not have to pay to any 3rd party. You will have full control over the server.
In this case of 3rd party like Mailchimp, GetResponse the SMTP Email Server will be their and they are charging you for using their servers on per email or per subscriber basis.
So instead of using that you can do the setup or heir someone to do it for you the complete SMTP email server setup instead of paying monthly for that server.
(see in the screenshot highlighted area.)