Labour is the least legally restricted property, money second, everything else third.
Money is less restricted than houses: HS reports that some guy was convicted for declining to sell his house to a Roma person, ie. for declining to trade a house for money. However he would (I think) be allowed to refuse to buy a house from one, ie. to decline to trade money for a house.
Labour is less restricted than money: it is illegal to refuse to hire someone because he’s a communist (decline to trade money for labour) but it’s legal to refuse to work for one (decline to trade labour for money).