And some information is so deeply buried that the cost of pulling it up exceeds its value. An information broker is in business. That means it's going to cost you money to get the information you need. Some brokers bill hourly, others bill on a project basis. You may be asked for funds upfront or for payment upon receipt or on 30-day terms.
Many information professionals have minimum fees.
Ask about these practices, and ask for an estimate of costs. All of these are valid approaches to billing. However, you should ask these questions early, and be comfortable with the response. However, you might want to probe further. Business practices also include the form the information will take when you receive it.