They are dotted everywhere on the island - especially in San An. The big record shop in the west end, Cafe Mambo, Savannah all have the discount flyers. The flyer for the Carl Cox night @ Space is everywhere. We picked this one up and got in for free provided we turned up b4 9pm - now that is a deal!!!!!!!!
The best way to get in to clubs cheaply is to simply sit on San An beach from 2-6pm most days and there are tonnes of PR people walking round giving away free wrist bands or discounted entry. We got free tickets to the Azuli night @ El Divino by sitting on the beach and was also offered countless other tickets for free for a whole range of things.
Also Bora Bora is good for free wristbands. We got free bands for Space, Amnesia, and Eden. At one point on the saturday we were there (two weeks ago) we had free tickets to Space, Amnesia, Underground, Eden, Priviledge and Es Paradis - all for that evening. We went and ate about 11pm and had a dam hard job deciding which event to go to for free.