As strange as it sounds, game development can be cheap hobby; especially for 2D. Godot is a free (in both beer and speech) and easy to use once you start learning. For art, use Krita or Aseprite. Krita is pretty normal drawing program while Aseprite is used for pixel art. Both are technically free (Aseprite is $15 but could be compiled for free). If you don't want to get create your own art, websites like [itch.io](https://itch.io) have free assets you can use.