Hey smiley64,
I've been at Riu Cancun last week and tried Basic, Dady'O + Ultra lounge, The City, Bulldog, Dady Rock and Coco bongo
The prices are vary between 40USD~50USD (coco bongo was the only 50$),most of them were 45$ pp/open bar, VIP section + one way bus ride to the Club (it was 5 minutes of walking back to the hotel),
my 2 bits, don't miss City and Dady'O. Basic is just so CRAZY! and hit the Coco bongo just for the show and not for a real nightclub. Coco bongo is not the place that you want to spend a whole night in. I personally prefer to go to a circus in my home town instead of wasting a night in lovely Cancun.