Scale plan pricing is customized to fit the needs of customers’ workloads. Runner jobs incur a nominal use-based cost, similar to our hosted resource classes. If you’d like to get more specific pricing for self-hosted runners you can talk to our sales team.
I’ve been spending time trying to get the Linux runner going and currently the documentation is hard going as it has not been updated from when self-hosted runners were something that was only available to people with support contracts. I think they are beginning to receive feedback to indicate that this area needs work.
In terms of costs, using a self-hosted runner will change your cost structure. It removes the cost of using CircleCI provided nodes (but you have to remember not to use the docker node created by setup_remote_docker. It also removes the cost of egress traffic from the runner that is going somewhere other than CircleCI’s internal systems (your systems or say DockerHub).
Once CircleCi introduces it storage and egress charges you will still be charged for any storage of Persist data held at CircleCI and any data that is sent from the CircleCI system to your self-hosted runner.
As for how these costs influence credits - beyond the included small monthly amount of storage network traffic each GB of usage is going to be charged at 420 credits. So depending on how you use CircleCI you may have to change what you are doing. For my situation, self-hosted runners have become a necessity as I need to build rather blotted docker images and so would see very high egress charges.