Portal/aggregator monetization. How to form a pricing policy?

Question

Marketing

For the life of any aggregator, two components are necessary. Users consuming content and some interested individuals who want to feed it to users (for example, on the Yandex market, these are online stores).
While there are no one on such a portal, others are not interested in it -> the circle closes.
But that's not the biggest problem. At the initial stage of development of such a project, the owner needs to "free" stir offers of interest to users and thereby attract them. This approach works for some time and is not bad at all, but when the first client writes to the post office, the newly minted owner of the aggregator has a question, how much can I sell my services to him?
Having recalculated everything by the standards of Yandex Direct and approximately estimated how many page views with the offer of his service the client will receive with the negligible traffic that exists at the moment, the owner of the under-business makes an offer to the client (let's say he agrees and constantly pays for this service). The price is extremely low. Everyone is happy, 3 months pass, the attendance of the aggregator doubles and the owner has a desire to follow this up by 2 times the prices for services.
And here a problem arises: the client’s unwillingness to pay more.
What are the possible scenarios for the development of events in such a situation?

• Offer a high price right away? After seeing attendance no one will ever agree.
  
• Increase prices every month following traffic growth? Customers don't like price increases.
  

What did you miss? How to get out of this situation?

Answer 1

In fact, the question itself already contains the answer.
If you initially charge the client not for the cost of an advertising contact, but for the cost of involvement, then there will be no questions related to the increase in cost, in the wake of traffic growth.
In general, the indexation of price offers is considered absolutely normal in the market. Moreover, you can always "attach" this indexing to real changes: traffic quality, new targets, etc.

Answer 2

Again, here I would go for MVP - since there is always an option for what the user will pay for:
1 - option for 1 unit of service / product,
2 - option for monthly service according to a certain tariff plan,
3 - option for a service package with a certain duration.