Ask HN: What to charge for my service/product

I recently built a website for a social media group for a local area, with 20k members very active in the group. The groups used as a platform for selling/buying, news, and just general discussions pertaining to our area. The site is fairly new, and I was thinking I would post articles about specific businesses, host events, and do some affiliate marketing with the businesses located here. I have no idea what reasonable rates would be for this. I imagine they'll be a good deal of traffic, and a lot of people reach out to us directly in email for local tips/tricks/questions. Another service we'd like to do is go to the business, take pictures/videos/etc, and do a write up about them and feature it on the site.

Has anyone done anything similar or have any tips when figuring out a pricing model for this type of business?