If you have a newsletter with 9k subs, how much would you pay to sponsor?

Genre: Movies and TV Shows
It's a vast audience since most of us watch movies or TV shows regardless.

I know the open rate of emails depends too, let's just say it's around 20%-30% .

Get Sponsor POV:
If you have a newsletter, what other factors do you count in and how do you set sponsor rates, etc?

Provide Sponsor POV:
If you want to sponsor your product or brand or service, how do you approach people with newsletters and your campaign rates?

I'm aware of some middleman sites like Paved or Kit etc as well.

Thank you for your time!