Case: Exact cost amount still unknown

[bschweighofer]

How do you handle the case when the exact cost is still unknown? For example, in the case when the invoice was requested from the author, but he has not yet responded.

Would the possibility of a searchable "note", in which it can be noted that the exact amount of the costs is not yet known, be a solution? The possibility of a searchable note (of some sort) would relieve us of having to periodically check for missing information.