As the title says do not start or join a small party. There are dozens of existing parties with hundreds or thousands of members, join one. I belong to a party with +68,000 members. Any of these parties will allow any or all to join. There are no risks joining an existing party: there is no information or identities shared within the party. You are not responsible for anyone else's bill. With a large party you never worry about someone dropping out and the party falling below 4 members to get the $25 monthly rate.