best way is to find a car to buy with rwc supplied. Just about all mechanics out there will want to make a dollar off you whether your car requires any work or not. In general if the car has good tyres, brakes, all lights working, seat belts undamaged, windscreen undamaged, headlights aimed correctly, no oil dripping onto the ground and no illegal mods then you should be ok. They usually charge around $150 for an inspection and certificate, you then have the option of fixing any defects yourself, having the mechanic or someone else fix them for you and then returning the car within 7 days for second inspection. Much easier to just purchase a car with rwc supplied. Don't ask me how I know