A channel's id from its @handle, its channel URL (youtube.com/@handle, /channel/UC..., /user/name) or the id itself (YouTube Data API channels.list): `channel_id`, `url`, `title`, `handle`, `subscriber_count`. A `/c/name` custom URL cannot be resolved without a 100-unit search, so it is a bad_input miss. Costs 1 quota unit.
Price: $0.00 per unit.
Maximum charge per unit: $0.00.