Some prices rise, some prices go down.
Ads aren't free money, the advertisers are paying for them (I know, seems obvious) but where do the advertisers get the money to advertise? Well, it's baked into the cost of the goods they advertise. That makes everything that advertises more expensive.
Lots of examples of this cycle you can search for.
Coca-cola, for example, isn't going to lower their prices in response to increased demand from their $4 billion marketing budget.