Gun Tower -$500 (Standard/Advanced) Basic anti-infantry defense.
Missile Turret - $800 (Standard/Advanced) Antitank and aircraft defense.
Mine - $100 (Standard/Advanced) Stealthy proximity explosive.
Infantry - $150 (Standard/Advanced) Basic rifleman, all-around attack.
Heavy Machine Gunner - $250 (Advanced) Short-ranged but tough against infantry and armor.
Missile Trooper - $300 (Standard/Advanced) Antitank and aircraft attack infantry.
Engineer - $500 (Classic/Standard/Advanced) Captures and repairs structures.
APC - $600 (Advanced) Carries up to 5 troops and has a rapid-fire machine gun.
Tank - $700 (Classic/Standard/Advanced) Main battle tank, decent on structures.
Advanced Tank - $1,000 (Classic/Standard/Advanced) Heavy tank, effective against structures.
Missile - $500 (Classic/Standard/Advanced) Explosive that hunts down targets and makes a good scout.
UFO - $900 (Classic/Standard/Advanced) Anti-infantry and -aircraft unit, relatively weak armor.
Gunship - $1,300 (Advanced) Ground-attack helicopter armed with machine guns and missiles.
Fighter - $1,000 (Standard/Advanced) Fast tactical attack aircraft. Good for surgical unit strikes.
Bomber - $1400 (Standard/Advanced) Slow heavy strategic aircraft. Good for bombing structures.
23 Feb 2011 Update: Added Heavy Machine Gunner to the list, the only non-naval unit addition to Battlezone in the 0.60 update.