If someone already has a job in practical world and doesnt need a lot of money then he doesnt need to put any money at all because he can earn a good part time income without any investment with signature campaign or other things, but if someone wants to earn a lot who is not having a job in practical world then he should think of investments.
There are some people who are eager to earn a lot of money online so for such people it is really important to invest quite a big amount of money to earn quite a good amount in profits.
And there are some people who just wants to earn as much as possible without investing anything so for those people there are ways that doesn't require any investment and that will give you enough for what you are wishing for.