the Zealot is the chepest Protoss unit you can build but it is quite capable of taking on multiple Marines, Firebats, Zerglings or even one or two Hydralisks and still win. the Zealot is a ground to ground unit only. the Zealot is a close range unit like the Firebat but it's very strong and a few of these are good for rushing enemies in a custom game. Zealots are best used when combined with Dragoons or Scouts for air cover..