Wow great feedback !
Economy is terrible in the game. Like people mostly wont play gamejam games, and I dont want to let them leave without seeing the windmill and the other stuff. How they are working. That is why they all really cheap. And you are right about the buying infinite cards. They will have some limit so you have to discard them. But I wasn't have time for it.
I actually take every feedback on my trello. And you make one giant feedback post is describing what I will going to do.
I think you have really solid points. I will update the game. Thank you for your time :D