It seems that email marketing isn't as simple as it seems. In fact, it is more complicated than it looks. You obviously need money to invest anyway. First and foremost is a bulk email sender program. Most recommend Atomic Mail Sender, but I got UltraMailer Sender Professional for free, but it is limited to only 300 keys. It is still promoting anyway. Second is SMTP servers, which are either free or cost money. Obviously it is going to cost money if you're sending over 20k emails per day. A Google search shows that there are plenty of SMTP servers out there and they aren't cheap. We're talking $300 or more per month depending on how many emails sent. PowerMTA is one most email marketers use anyway. Interspire is another one most email marketers use as well. Free ones like Gmail, Hotmail, and Yahoo place severe limitations on sending emails to either 100 or 500 per day. Third is a VPS (virtual private server) since this is what you will use to send emails from or else your ISP will cut off your Internet service for good. Most email marketers go with Linux VPS along with Interspire. Fourth is a domain and hosting. Most people want to buy them cheap off GoDaddy, but there are others you can choose.
Email marketing seems to have a sizable investment anyway and payment to set it all up, but most people are able to make decent money on it. Biggest problem is that this will be considered spam and you won't be able to send your emails to inbox properly.