A: Hi, thanks for your question.

There's no need to purchase list from a third party. The list should ideally be your own domain's subscribers — people who have subscribed to hear from you.
You can collect your subscribers using a form on your website. In that case, you can also use MailBluster's built-in forms. Here's a helpful guide to get you started: https://mailbluster.com/blog/mailbluster-forms.