Well the amount your going to have to pay depends on how many Degrees of Freedom(DOF) you want your robotic arm to have. Different strength servos/actuators will be needed for different parts of the arm. Describe your arm a little bit better.
"The base can turn 360° on the Y-Axis. The arm can move 90° up and down on the Z-Axis at the base. There is a single elbow that can turn 180° on the X axis and 180° on the Z-Axis. Then at the end is the hand which can turn 360° on the X-Axis at the wrist."
Axis description when looking from the front:
X: Side to side
Y: Top to bottom
Z: Forward and back
Sorta like this:(Click for bigger view)