trying to get an object to follow mouse on GUI click

what i am trying to do is have a prefab follow my mouse when i click a GUI button then when i click again i want the object to stay there. im having trouble getting the object to move after i instantiate it. how would i make the object follow my mouse after instantiating? is there a way to do this using the DragRigidbody in the Standard Assets?

I think what you want is info on click to move and then just basic knowledge of boolean functions and the GUI function to use 2D on screen buttons to turn sections of script "on and off"