Examples (from another thread):Power supply: http://www.circuitspecialists.com/ps1-150w-28.html (24V, 5.5A, $42.88)Controller: http://www.circuitspecialists.com/stepper-motor-controller-xcw220.html (0.4A, $29.50)Motors: http://www.circuitspecialists.com/nema_23_stepping_motor_57bygh207.html (8 kg cm == 6.97 lbs in for $13.95)Does it have to be battery powered? "Pick and place" generally means it's an automated manufacturing machine (such as for populating electronic circuit boards), and thus typically plugged in.Also, driving half an amp or more per winding per motor from a LiPo battery sounds like it will deplete available power in a hurry...
For just a high school project, a servo based arm might be easier to get started with. Search on youtube for "servo arm" and similar for examples.
If you can give an estimate of the speed the motors need to go (in degrees/second or rpm) that is useful - making steppers go fast can be an issue.
As I've stated I built a servo based arm already but I'm looking for more precision movement, that's why I'm trying to use some stepper instead of servo, to get rid of radio control completely to decrease human error as all objects location are known prior to the competition.