Newbie fundamental questions (motors, etc...)

[RobotArms24]

Check out http://www.pololu.com for motors, they have a bunch of metal gear motors of all sizes and RPM's. They also sell the TRex motor controller to control two motors, in a tank style setup.

Another common controller is the Sabertooth motor controller from https://www.dimensionengineering.com/

A good site for parts is http://www.robotshop.com. They also have a Canadian website.

Robot shop has Firgelli actuators to control the buckets and lift arms, a bunch of servo's, and tons of other electronics.

If you are on a budget and have no time deadline, http://www.hobbyking.com has lots of R/C components for cheap.