I think a good solution to this is to limit how many promotions or “impressions” a room can buy depending how many active players they already have.
For example if a room has 0 active players online in a given day, the creator can buy 10k impressions for that room in a day or week. (Or whatever limit is imposed on impressions as there are a limited amount of people who can see those impressions in a given day.) If their room looks attractive they will achieve a good impression-to-visit rate.
For a room with 100 active players in a given day, they will be limited
on how many number of impressions can be purchased, like 1,000.
I think the pricing should be around 1-10 tokens per impression, as I found that the average tokens earned per visit on rooms is generally around 10 tokens.