Why do prison emails cost so much?

I’m soliciting prompts for discussion. This piece is a part of that series.

An anonymous reader asks:

‌Why do emails in jail cost 50 cents each?

Since around 2016, US inmates in 43 state prison systems and the Federal Bureau of Prisons have been able to send electronic messages of a sort. Recipients must be whitelisted and all messages are screened. The up…