Speaking rates vary depending on the type of event and the amount of travel and preparation required. It is assumed that all air travel / hotel / car travel will be paid for by the event organizers. On top of these basic accommodations, a speaking fee will be agreed upon. I’ve used a few different frameworks for establishing a flexible speaking rate. The first is the “five attendee tickets” rule, which uses the full-price cost of a ticket to the event to determine the speaking rate. If a full-price ticket costs $1,500, the speaking fee would be 5 x $1500 or $7500. If full-price tickets cost $50, the speaking fee would be $250. This allows me to lower my rates for small events geared toward (broke) students. The second framework is based on day-rate pricing (in which the rate on the day I speak is my full day-rate and any other conference or travel days associated with the trip are charged at 1/2 day-rate). This framework can be more useful for events involving international or long distance travel or those requiring new talks to be written.
When it comes to availability, this can vary depending on what projects I have on my plate. I prioritize events that allow me to have the maximum impact with minimum time away from my family. It is easier for me to travel during the work week than on weekends, and for the time being I am unavailable for events that require being away for more than 3-4 days.