There are so many big lists of the people craving for more information or solution to their problem.
Expert marketers have already get their emails in their lists and can send newsletter direct to their inbox.

So buying an ad in related newsletter will bring a targeted traffic to your website. Which will of course result in some more sales.

To get maximum benefit of your ads, DO NOT ADVERTISE. Yes, instead offer something free and get them opt in to your own newsletter.
Wow, you are in position to run many more ads to the same user with no more cost. That is no more Buy website traffic!

So run ad in highly related newsletter to your product with the professionally written ad copy offering something free to get them to your own list.

If done intelligently, this type of advertising can result in more sales and revenue.