How To Animate In Blender Grease Pencil
Blender is FREE and is now being used a LOT more in the animation industry - if you already know the 3D tools well, adding Grease Pencil animations to your skillset is an easy way to get into 2D.
If you've never animated in Blender before but want to learn how to make 2D animations with Grease Pencil then my Beginner Guide (linked video!) can definitely help with that :)