Great question! So I have a content mix of selling/serving. With the monthly promos I like to think of them as "themes" for the month.

For example, if I'm talking about the importance of youtube, the first 3 weeks are going to once a week newsletters where I talk about youtube content creation, how to do it, strategy, etc. If people want to have a deeper dive on my content beyond the newsletter I redirect them to Medium > which provides value to the user and allows me to get paid*

Then the last week of the month I promote an affiliate product that would help them with youtube content creation because I've been talking about it for the past month. Does that make sense?

Believe me, selling only happens AFTER you've served your audience. Serve first, sell later.