you need 50.000 credits for joining a clan.
it's system tax.
most clans refund this + giving a bonus out.
additional costs depend on clan tax.
which can be from 1% up to 5%.,
where every member pays this percental ammount of his own credits into the clan fund.
this fund can be payed out by councils or leaders.
get more specefic information by going into the clan search section of this forum.
leaders of clans ( if interessted in you ) will inform you about their conditions.
have a nice day