> At conferences I've attended I think it's extremely rare to have a speaker be compensated (maybe outside of the cost of flights/hotels)

Flights, hotels, and tickets are all compensation and what I was referring to. These conferences are all open to newer speakers.

> Also, it's more than reasonable to expect someone to rehearse,

Apparently not, judging by comments.

> but I don't think there is any substitute for the real thing.

But you don't need to go from not speaking to speaking at a conference. There are many other steps in between where you can get experience in public speaking.