Mentioning money in statement of purpose
Actually its well known that research assistance-ships pay less than regular jobs. This is true.

But, I think you should not mention money in the research statement in a blunt way. But you can definitely prove your point in a subtle way:


  Like, After my undergraduate I got multiple offers from multi-national corporations but my passion motivated me to choose a research path over any other.


This is just an example, you can rewrite suiting to your needs.