How much does it cost to join a community in addition to the ones that come with my membership? ATD KB Admin Updated October 14, 2016 19:23 Follow All ATD Professional members are able to select four communities. To join additional communities, there is a fee of $30 per community per membership year. ATD Professional Plus members have unlimited access to all of the communities’ content. Related articles What is a community of practice? How many ATD communities of practice are there? How do I determine which community of practice to join?