maybe you can start a new casino at a cheaper one but if OP is telling the truth about a profitable casino, then investors might consider this. Im wondering though why theres a need to sell it if its profitable, that profit can get him a loan so he can finally buy a house. Well, this is the decision of the owner so probably he knows better, but it will not be easy to sell this casino on its asking price.
The only problem about starting a new one is the competition. You will still need to spend to advertise your casino heavily and then spend on the developer to make constant upgrades.
All these hassles are going to be skipped if you will just avail an existing casino but that is if you can afford their pricing but it is still possible for us to recover what we have spend in the long run and then make more as long as we know how to manage the casino well. The op already stated a reason in the first page on why they want to sell the casino. It's not only about buying a house because if they do then they will just follow what you suggested there.