Advantages of Buying a Used Bus from Rocky Mountain Bus Sales The biggest advantage to buying used over new is cost! To be able to buy two used vehicles for the same price as one new, is huge for most of our customers. Because we buy our used busses from Colorado customers a place famous for mountains these buses typically come with more powerful engines and transmissions so our used bus inventory is simply are stronger and superior to "flatland" busses. The buses we have for sale are heavy specd buses with 210 horsepower or greater and have heavy duty transmissions so theyll last longer.