[throwaway3neu94]

Fortunately that's not something you can buy.

These contacts are occasionally scheduled with organizations (schools etc.), but unscheduled for the general public.

Exchanges tend to also be one short question (how does earth look from above right now?) and one short answer (earth looks beautiful), and then it's on to the next person. Not just due to congestion, but also because the ISS is only visible for a few minutes.