There are people working for very little, but it is very rare. For example you make at least $15 an hour at McDonalds in Sweden since that is what the union agr

There are people working for very little, but it is very rare. For example you make at least $15 an hour at McDonalds in Sweden since that is what the union agreement is for that sector. McDonalds isn't forced to sign it, but if they do they are protected against strikes. However you can have a small company without union agreement and pay whatever you like, but if your employees are in a union they might use it to start a strike action if your conditions are too bad. Note that in Sweden unions aren't company specific so there is no way to prevent people from joining one.