Chargebacks refer to the pricing strategy where the costs of cloud services are passed back to the departments or business units based on their usage. This encourages responsible resource usage and helps organizations track and manage their cloud expenditures. On the other hand, showbacks provide visibility into the costs incurred by different departments but don't necessarily charge them back. A flat fee model involves charging a set fee regardless of resource usage, and a pay-as-you-go model charges based on actual usage without explicit departmental allocation.