Assuming you have other needs taken care of, like love and whatnot, money DOES bring happiness. The more money you have, the more freedom you enjoy, to do whatever the fuck you want. The more freedom you enjoy, the happier you are, as you don't have to worry about restrictions, be they of material or other nature. Don't know who said it but "I've been rich and I've been poor. Rich is better" seems spot on.
"Money doesn't bring happiness" is possibly the biggest crock of shit in history, right up there with religion. Must've been coined by some stinking rich people, in order to keep laborers happy with their low level of wealth, so they don't try to get rich too.