It really depends on the person on how much he or she can really invest his or her money. The profit or his gains will also depends on how much he puts his money for investment. It can be a percentage of one's salary.
People here in my country when they found something that's going to be profitable they are investing to it and they are fully blasting their savings as long as they have the promise that money will go back again to them. But as a normal citizen here, I will not going to invest without knowing what I'm going to invest and I'll only invest what I afford to lose. Don't invest more than you don't want to lose.