A good discussion of free coupons as well as a list of links. Watch out for the Rio buffet for locals as you need local ID.
The 24/7 magazine on line is a very good deal. Solo tip is that the V show coupon gives 50% on the Vegas Review rather than just 2 for 1. Always in the V give plenty of time for purchase and for finding the theater. It is a long and confusing walk.
Currently I also like the Divinci exhibit coupon but I think it will be gone before I have a chance at booking a trip.