How to get e-mails to send "spam"?

I am starting from scratch in the world of affiliate marketing, and I say from scratch referring to both knowledge and money to invest.

I have seen that email marketing is very common and even more so if you don't have a website with traffic from which you can get customers.

My question now is: how can I get lists of emails to send my affiliate link to?

If you know any guide or advice is welcome, thank you.

Promote your blog and collect emails list from customer that's it