Or, if I stay on the east (Flamingo, Harrah's, MGM Grand) side of the Strip, I occasionally go via the Las Vegas monorail. Usually, I buy single-ride tickets @ $5, unless I plan three or more rides in a single day ($12/day). I'm cheap; I like to save the $2 and give it to the room maid as a tip.
By the way, if your party is three or more, it's a little cheaper to get into a cab.
A small bonus: An event/attraction discount coupon booklet is available at each station. I almost always pick one up ... I just never use it.
The only problem is that although the monorail stations are attached to the various casinos, the walk from the station into the casino is pretty long. And if you want to visit a casino on the other side of the Strip, the walk is even longer. When I have to do that, I just hail a taxi instead because the old people in our party can't handle the walk.