After reading your question, I went to check the accommodation status. https://castelhaller.ro/rooms-list-view/
This is the link to accommodation in the castle. Prices are in RON, which is the Romanian currency, but to give you an idea, 1euro is close to 5RON.
However, I don't know where to check for those rooms I showed in the photos. Those must be way cheaper as those are of a different category.

Staying in the castle is nice as not many have had the opportunity, however, at those prices 😳... 😂 there are better ways to spend that money. I could see myself spending a few days in the small house, just to rest and enjoy the scenery, have long walks and enjoy the local cuisine.