Las Vegas is a town flooded with coupon booklets, line passes and opportunities for discounts. You'll find booklets in a pouch on the back of the taxi seat, more than likely you'll be given one when you check into your hotel and there are any number available for purchase either before leaving on your trip or after arrival.
With all the booklets, passes and "nightclub passports" (a very fancy name for a line pass) available, the basic question is this: Are they worth it?
The answer: Maybe. Depending upon how much work you're willing to put into stretching every penny.
Coupon books and the like can definitely save a person a bit of money (not a giant amount, but noticeable) but at the cost of flexibility in your plans. You'd need to eat at certain places at certain times of day in order to take full advantage of the coupons, for example.
Some travelers have a great time planning their itinerary around discount offers. To them it's kind of a game to see just how much they can shave off of regular Vegas prices. Other visitors prefer to remain fully flexible in their schedule -- they want to eat whenever and wherever the mood strikes me, using the dining example, even if it means paying a little more.
The upside is that the books themselves aren't very expensive (or even free), so the risk in purchasing is low.
One thing that is almost always worth doing is to sign up for text-message special offers once you arrive. Almost every casino has these available now; you'll likely see multiple signs for them when checking in. The text messages only come for a certain number of days -- generally something like 9 offers spread over 3 days -- and sometimes the offers are pretty good. (Do keep in mind that if your phone carrier charges for incoming texts, you will be hit with those fees.)
Selected coupon books, line passes and other discount offers