The cheap battery load testers like this
http://www.ebay.com.au/itm/BATTERY-L...IAAOSw9eVXVl6m work fine for load testing and the scale on the gauge is calibrated to show the reading for different CCA batteries. They are really only useful when a battery is not holding it's charge and you want to know if the battery is dying or the charging system is at fault; but in those situations it is extremely useful. The carbon pile ones like this don't tell much more (essentially just a current reading)
http://www.ebay.com.au/itm/Battery-L...UAAOSwtJZXW3dy
A clamp on AC/DC multimeter is useful as it allows you to more readily test the alternator output by placing the clamp around it's output wire to measure amps. A clamp on meter also allows you to more readily track parasitic drain by moving the clamp along the wiring harnesses from the battery to the drain source. Like this
http://www.ebay.com.au/itm/Pro-Serie...EAAOSwv0tVXPP7
Watch out and read the spec carefully before buying a clamp on meter as many like this
http://www.ebay.com.au/itm/New-Clamp...kAAOxyf~hRzZ0n while describing themselves as AC/DC clamp on meters, only read AC amp with the clamp function. Jaycar and Altronics both sell suitable clamp on meters such as
https://www.jaycar.com.au/400a-ac-dc...meter/p/QM1563 and
http://www.altronics.com.au/p/q0968-...c-clamp-meter/