Used Car Salesman is a Halo 3 achievement. It is obtained by destroying a vehicle with three or more enemies in it in either a ranked online playlist or in campaign. Unlocking this achievement gives the player the Scout Helmet for Spartan Armor customization, it also awards the player five gamerpoints. It is represented by an eight-pointed yellow star on top of an eight-pointed red star. On top of this are three white stars.
An easy method to get the achievement is to start a campaign mission where there are enemies on prowlers, then weaken the prowler with weapons fire or frag grenades, then destroy the vehicle with a rocket launcher, Spartan Laser, or a Plasma/Spike grenade stick. You can also do it rather easily by using scorpion tank to blow up a prowler (only on the covenant), however you may need to ensure that the marines can't kill any of the brutes on the prowler.
Alternatively, you can also destroy the front turret of a phantom during a campaign level. This can cause a glitch which unlocks the achievement, as the game thinks the phantom is destroyed when only it's turret is. There are many levels that provide this opportunity: Sierra 117 (After saving Sgt. Johnson), Crow's Nest (When clearing the Hangar), Tsavo Highway (Before acquiring the second Warthog), and The Ark (When ambushed by a Phantom in the Cartographer).
- Main article: Multiplayer
The easiest way is to get it on a large level with Warthogs, Scorpions, or Prowler, like Standoff. Grab the Rocket Launcher or the Spartan Laser. Wait for the other team to grab a Warthog and destroy it. It is best to do it on a CTF gametype, since their players tend to use team vehicles.
- Scarabs do not count as vehicles for the purpose of this achievement, as the enemies must actually occupy a "seat," rather than merely stand aboard the vehicle.
- Destroying a Phantom itself instead of the front turret will count for this achievement, so long as the side gunners are still alive when the vehicle is destroyed. An easy place to pull this off comes in Crow's Nest if you take over an HMG turret and restrict your fire to the ship.