Jumbos are the main form of public transport in town. The price anywhere within a 3km radius is US$0.50 to US$1 per person. A ride to the airport will cost US$1.50 per person.
Cars and 4WDs can also be hired through the guide services at Sousath Travel at the Maly Hotel or through just about any guesthouse or hotel for jaunts outside of town.
You could easily visit all three Plain of Jars sites by bike or motorcycle. Guesthouses can help you find motorcycle hire (per day US$15), and Craters Bar & Restaurant has two bicycles for rent (US$3 per day).