When asked to speak as a guest at a very large conference, is the guest expected to pay full price to register for the event?

I have been asked to speak at a “Global Summit” in Washington DC. Today I received my formal invitation in the mail.

It told me that I needed to register for the conference to confirm my speech time.

I am not being compensated for my airfare or hotel, nor am I being paid for my speech. Am I wrong thinking that paying $500 to attend the summit that I was invited to speak at is a bit unreasonable?

Do any of you have experience in these matters?

The invitation alluded to “As is customary at such summit meetings you need to register.”