98% of the groups are free. New York, LA and the Bay Area groups there is a 49.95 fee for. Those are the three most popular groups, which means a higher demand. I have to make some money somehow. The last activity in that group was yesterday. I'm not sure why it says that. NY gets lots of email blasts of work. If you don't want to join the group, just join the groups around that area that you'll cover.
If you're looking for more work, don't forget to hit on the Cover Depos tab on the top of the main page, hit the red dot on the map where you'll cover work, and then click on the tab to "Join the Group." Once you do that, your email address will be saved with everyone else's email address and you'll receive email blasts of jobs in your area. You just contact the agency directly from the email with their contact info.