It's been quite a while since I've been to a dungeon, but the standard assumption was that the house took a cut, often 60%, and clients were expected to tip some amount -- 20% and up -- on top of that. I've never heard of a house taking 100%, and it's weird to expect a client to have an extra $300 in cash in his pocket. Would be curious what house you are speaking of (as far as I know, NY only has two or three.)