The Coast hotels have a shuttle - so between the orleans, gold coast, and barbary coast is covered. Once you are either at the orleans or the gold coast a taxi ride to the palms or rio should not be too expensive.

There is also public transit up and down the strip (to downtown for example) that was pretty easy to use from outside the flamingo. Plus the trolley between the hotels.

Last time I was there (a few weeks ago) I was able to get a very good rate from hertz for their smallest car class for $14.99 a day and that worked out a lot better than having to rely on shuttles.