All members of the Communist Party are expected to support the party financially. Membership dues are generally paid annually but can also be paid month-to-month. Dues go towards sustaining the party's resources (such as this website) and ensuring its ability to provide material aid to the efforts it actively supports.
For new members, remember that your membership in the party is only official after your dues are paid as well as the $1 initiation fee paid in person at a party event. After your dues are received, you will be given a membership card and you will officially be a member of the Communist Party.