Is there a way to get some without having to pay?

Hi, you have to get some recruits. Go to the section Premium - Hydrian crystal - Earn.

There you will get a link. Those who will use it will be considered to have been recruited by you. When registered they become your vassals. You will receive Hydarian crystals for their accomplishments.

Is there somebody who knows how could I take out hydrian crystals i get for recrutis from Federal Reserve Bank?

Polonius,
in order to be able to take out the crystals you earn from followers, your follower needs to reach 25k points, first.

One crystal is given for each infrastucture, raids, battle level.