Is there a good budget priced castle in Ireland or Northern Ireland where five adults can stay for one night?
There are several budget castles in Ireland that you can check. I have found the following link where you can take a look and see if you can find what you’re looking for. http://www.irelandyes.com/castles.html
Hope this helps.
I have stayed at Belleek Castle in Ballina, County Mayo. It is set in the beautiful northwestern part of the Republic of Ireland amidst scenic grounds. Even though it is not what I would consider “budget,” the prices are not outrageous either. Give it a try!