Compare

Is it worth listing unsold space at all?

Unsold space earns nothing: in the trade it is called unfilled inventory. Listing it costs time, and that time is the real question.

PointAdvoratiseLeaving the space unsold
Cost to listFree. Commission is taken only from money you actually earn.Free, and it earns nothing.
Time neededAbout ten minutes for a first listing, then minutes per booking.None at all.
Unfilled spaceIt can be sold at a flat fee you set yourself.It stays unfilled every issue.
ControlYou approve every advertiser and can refuse whole topics.Nothing to approve.
RiskYou can pause or remove a listing at any time.None.

Where the other way wins

If your audience is small, the money from one placement may not be worth the ten minutes, and an empty slot promoting your own work can be worth more than a paid one.

Best for

Anybody with a regular audience and no advertising income today.