Godot engine vs Cocos2d
Cocos2d is obviously dedicated to 2D game development while Godot can be used to make 2D and 3D games .
Both engines are open source and free so you won’t find any problems regarding your first budget .You can use them for free and sell your games without paying anything to game engines owners ,which not the case of many popular and widely used commercial games engines like Unity engine as an example .
You can use Godot engine either with C++ or GDScript which is a small set and focused version of Python language .It’s easy to learn and use .Recently you can also use C# for developing games with Godot engine .
Cocos2d is a very proven 2d mobile game development engine .Statistics show that 25% of 2d games created for IPhone are built using Cocos2d-x which the C++ version of Cocos2d family of engines .