Quoting AppleStore:
Everything good with the goodwill and that. I mean that's your right if you want to offer your apartments for free. But the fact is still that you own all retail stores in Helsinki, and offer your food (which by the way is the only thing the NPC and most people buy) for 25 USD. You even placed some more expensive stores in Helsinki where you offer the food for 50 USD, so a newbie would think that they have a great deal with the food for 25 USD.
Meanwhile, we "poor" people need to compete in New York and Los Angeles, where the land cost is higher and the population is a third of that in Helsinki. I currently offer my food for around 10,50 in my New York store, and that is the only way to get any sales as a store owner (which I don't want to name drop) keeps dropping his price more and more. So where we would get around 3 USD profit per food sold, you get 18 USD. For that profit margin, I would gladly PAY my apartment renters 5 USD to live in my house.
You can pick any price and margin you like, it's completely up to you.
Here's a free tip:
It's a completely free market, nobody is stopping you from making pricing agreements or even paying someone to increase their price or to stop selling for a week if you think that can benefit you. Or you can choose any of the many other possible option's to try and improve your margins, and it could be a win-win for everybody involved, but working with other players is completely based on trust, a player can decide to 'backstab' you in the process. You can also decide to just compete on price and keep lowering it. Just make sure to be smart about your strategy or other players can disrupt the process and/or want a piece of the pie, which can end up costing you some extra margin.