@William *********
AirBNB is legal if it's 1 month or longer. Short term AirBNBs of a condo are illegal (but still commonplace).
The only problem you can run into is some AirBNB hosts will not file a TM30 for you even though it's required by law. Sometimes you need this TM30 to get your extension at immigration so that can be a problem.
They don't want to do it because they're not paying taxes on their rental income and they do not want the government to know they are renting.
So I generally message the host on AirBNB before I book and ask them if they will do TM30 for me. If not (or they say they don't know what that is) I just keep looking.