# Cost models

The rules that determine which advertising events are charged and how prices are calculated.

The rules that determine which advertising events are charged and how prices are calculated.

## An example

One campaign pays per click while another pays per thousand impressions.

## Why it matters

A lower unit price does not necessarily mean a lower cost per useful customer outcome.


## Related terms
- [Ad placement](https://jolts.xyz/resources/glossary/ad-placement)
- [Ad spend](https://jolts.xyz/resources/glossary/ad-spend)
- [Advertiser](https://jolts.xyz/resources/glossary/advertiser)
- [Publisher](https://jolts.xyz/resources/glossary/publisher)

## Next step

[Explore advertising](https://jolts.xyz/advertisers) or [monetize your AI app](https://jolts.xyz/publishers).