You can have $1bn and be totally miserable and miserly, you can have .15 and be generous and happy, and vice versa.
On what planet? You aren't going to be happy begging for food, walking everywhere you go, having no place to shower or sleep, not having clothes, etc. Certainly, each extra dollar gives you less marginal happiness as you move up the net worth scale into the tens and hundreds of millions of dollars. But if you aren't able to meet a certain reasonable minimum standard of living, you will be absolutely miserable.
For some people their minimum standard of living dose not require money. Buddhist monks[1] come to mind. There are also people that simply want to live away from society and thus have no real need for money.
[1] http://www.buddhanet.net/e-learning/buddhistworld/layguide.h...
(To give some examples of lifestyles that do not require income, nor external people paying for things.)
But the larger point stands, your state of mind and your access to resources are connected, very strongly at the poverty end. There are definitely people who can be very fulfilled with very few resources (until they get sick or it gets very cold) but they would all be happier with a bunch of money, even if that's just to give away to those in need.
If you have $100 in the bank on a good day, then your trips to the grocery store play out a lot differently than someone who has even $1,000 in the bank.