You get unlimited private repositories, 5 project users, 50 GB of storage, and 50 GB egress per monthly for free.
Monthly overage charges beyond the free quota are $1 per project-user, $0.10 per GB of storage, and $0.10 per GB of egress.
So for 10 project-users, 100 GB of storage, and 200 GB of egress in a month, you pay $5 for users, $5 for storage, and $10 for egress, for a total of $20.