You may not have seen this on the FAQ page.
https://www.steemithelp.net/#/logging-in/

This, combined with the huge current demand for accounts is resulting in delays - in some cases people have waited 7 days or more before their account has been activated.

The reason for the cost is that every account on Steemit/Steem costs a certain amount of Steem (the currency) to create. Normally the Steemit company pays this for you - this is also one of the reasons they are cracking down on people making multiple spam accounts.