TOPIC: Payment amount TBD (To be determined)

I run a site for an organization that twice a year hosts training events. I know the dates of these events 6-7 months in advance and start setting up the "event" under DTregister. Is there a way that I can set the event fee to TBD? I won't actually know the costs until 2 months before the event, but would still like the event listed as upcoming. Zero in the fee field means free, and that is very misleading.