Using variables in Logic Editor I'm quite new to Blender's game engine, but I'm trying to give it a go now.

My first try was to create a simple WASD keys character movement using the logic editor.

For that, I needed to set the Loc (location offset) in the motion actuator for each keypress, but since they would be all the same value, and I could want to change them at a later time, I wanted to use some kind of variable to control it, like "character_speed". I know this seems like an overkill, but I'm thinking ahead for keeping things organized for bigger projects.

Is there support for something like that? Maybe using python scripting or drivers?

Thank you!
you can add custom properties to any object in your scene to store simple data types like an integer,string,boolean,float or a timer variable.  

The property sensor allow you to test their values , and the property actuator to affect to them new values.
the controller can do logic operations to combine tests and trigger different actuators.  

for complex data types , like arrays and structures, you have to use a python script.