New to this

From My Experience I will suggest you to start with MailChimp.
Email Marketing Field Guide | MailChimp
Video index | MailChimp.com
Also for newsletter subscription forms to display on your website (if wordpress) use this plugin: Thrive leads. They have many features and very easy to use and integrate with mail chimp.
Also start working on something to offer to your subscribers to attract attention and encourage them to subscribe. e.g. Free ebook, giveaway or discounts.

Try buying solos from communities like Udimi or Face Book Groups. Buy a WSO here on List Building and see how other people do it.

What kind of list do you want, people who opt in for a free offer or a buyers list of people who bought a product from you?

Obviously the best kind of list is a buyers list of people who bought a WSO or other product that you have promoted. Unfortunately it takes a lot of work to create a product and launch it.

So buying solos and directing them to a free offer through a squeeze page is an alternative to that.

Even if you are sending traffic to a squeeze page you should have an optimized sales funnel in place with one or more OTOs that are presented to the people after they opt in for the free offer. You can even direct subscribers to affiliate offers in your funnel.

Or you could find a high quality PLR or white label product that you can sell and you can modify if it allows. You can either take those products and sell them as is or you can re-purpose them.

In order to re-purpose the PLR you will need to create new graphics and rewrite the content a bit. If you can't do that yourself then you can hire writers and graphic artists on Upwork, Elance, Warriors for Hire, etc. Do a search for something like "top freelance sites"

Cheers!