hi:
I would like to make a robotic arm with two motors step by step, and at least five servos but i don´t know that is the cheaper board that i can use in this proyect
thanks.
Do you mean two stepper motors plus 5 servos ?
A lot will depend on how you control the stepper motors. If you use a specialized stepper driver (you should) each motor will require step and direction connections to the Arduino. If you use a h-bridge each motor will require 4 connections. That is also true if you are using the little 28BYj unipolar steppers and a ULN2003 driver - or maybe they need 5 connections each.
Each servo requires one control connection to the Arduino.
You may also have other things that need to be connected
You need to count up all the connections. If an Uno does not have enough I/O pins you will need a Mega.
...R
Stepper Motor Basics