Earlier quoted context omitted.
Money can't buy happiness, but it can buy less unhappiness. There's diminishing returns, of course, but I'd hazard it looks a bit like ln(n), in that the returns are quite significant in the beginning.
Money can very much buy happiness. Most of the things that make you unhappy can be remedied with money. How much money you need to accomplish that depends though.
1: not unhappy is weird phrasing. Substitute not sad or not angry or not hungry or whatever for your particular state of unhappiness.