While it's not possible to choose one repair manual as the best, Auto Zone offers a wide variety of free vehicle repair manuals online. A user needs to know the year, make, model and engine type of the vehicle he is interested in repairing to access the correct manual.
Even though Auto Zone offers a wide library of online repair manuals, its catalog is not comprehensive. Haynes Online also offers a wide selection of repair manuals available for purchase. Haynes Online repair manuals can be purchased for approximately $29.99 as of 2015, but the price may vary depending on which vehicle repair manual is selected.