Citiwalk is actually outside/in-between the two Universal theme parks and does not have an admission price for access. However the Nightclubs do have a cover charge after 10pm(?) with an all access pass available for about twenty bucks. Citiwalk is like one gigantic street party and is fun even if you do not pay for the Nightclub admissions. There are shops, Restaurants and a cineplex. Often there is entertainment at a Center Stage that holds crowds attention and adds to the fun. Plus, as a resort guest, you can also take a boat over to the other resort, Portofino, and stroll through their common areas.
HAVE FUN