Should I buy an email list?
TL;DR: No!
It seems like about once a month, I'll have some new client tell me that they're going to buy an email list as part of their Ghost newsletter launch plans. (Sometimes they ask me to import it for them.)
Here's my response:
Please don't buy a list. There are no good lists for sale. No one can sell you their list, because those users haven't opted in to hear from you – they don't even know who you are. Furthermore, email lists for sale are often full of garbage email addresses. They have honeypots and spam traps. They have a lot of addresses that bounce. And they have really pissed off users whose addresses are getting hit with a ton of unsolicited emails (because you don't think this email list got sold just once, do you?), who are now reporting every unsolicited message they receive as spam.
If you can find a legitimate existing email list whose recipients are the people you're trying to target, don't buy it. Instead, ask the mailing list owner to let you sponsor a newsletter, or provide a story about your site for their newsletter, or to otherwise include information about your site in their existing mailing. That's not spam. And it's much more effective than buying a list of unwilling recipients.
Sending email to a bought list will seriously impact the deliverability of everything you send from your domain in the future. Once your domain gets marked as being a source of unsolicited spam, it'll be really hard to ever get a newsletter or even an email "magic link" delivered without having it tagged as spam. It can also get your sending privileges revoked by your host, or even get you de-platformed. Not kidding. No one wants to host spam.
If you want people to hear about you who haven't already signed up to hear about you, then you need to either buy advertising somewhere, or generate organic chatter, or use social media. Or if your target audience is local, go to local events.
Look for ways to share information about your site that aren't "cold email" (spam). If you frequent online fora or social media sites where your target audience is, look for ways to link your content, occasionally, and in ways that are helpful, and not spammy. Do you have a blog post that describes how to solve another user's problem? Offer a link to it. Does the forum have a showcase/share your site section? Post a link to some of your best work. This works best when your posts are authentic, and it's clear that a real human who is a member of the community is participating in discussion. If what you post looks like an AI wrote it, from a five minute old account, it isn't likely to survive moderation or get clicks.
Make great content, share it with people in ways that are logical, helpful, and non-spammy, and some fraction of the people who visit your site will subscribe for more.
But please, don't buy a list.