You could get around Abu Dhabi for a reasonable cost if you use affordably priced public transportation options. Those looking for the optimal way to travel within this city for a moderate cost can make use of the local bus services which would take you to many parts of the metropolis. You will find that the fare system for public buses is relatively simple; there is a set rate for rides in the city, a somewhat greater fare for regional travel, and a fixed price for a pass that enables you to use the bus system for a month.
As this city happens to be fairly compact, you could make your way to many attractions on foot as well; just keep in mind that jaywalking would be illegal, and the daytime temperatures outside could be high during the summer. You could also consider renting a bicycle and head off on pedal-powered adventures.