Wanting to trade up

[Snugglebutt]

Selling your house is and isn't against the ToS. If you sell your house for a price near your purchase value, then GMs will leave you alone. If you attempt to sell your house at a significantly inflated price and get reported the GMs will punish you. See this thread for the details.

People have been banned for selling theirs for far less than the plot value (less than half it's plot value in some cases) and still been banned. You shouldn't tell people the GM's wont do anything if merely sell for a low price since they have banned people for doing that too. Sometimes people get away with it because the GM's did not find out about it but the idea that they won't do anything just because not charging a lot of gil for it is false.