first of i apologize that i leave this as an answer as i can't comment.

just as Slava commented, it would be nice to see your .devcontainer/Dockerfile

i am assuming that there was no problem running your docker-compose file until you tried to conditionally run your celery related containers. so i think it would be helpful to know the commands you used and the order you would start your app.

also as long as the celery worker using the paid API isnt executing any task (ie. using the paid API to do something), i doubt that you will be charged just for the celery container to be up as it will be in an idle state.

hope this helps.