Some of the happiest people I've known are broke, while some of the most miserable and stressed are well off.
I've lived my life from both sides. I have been broke, then wealthy, then broke again.
I can tell you for a fact, money can buy you moments of happiness. It can give you material things that make you happy but the happiness from those things doesn't last long. Money can't buy you Health either...David Bowie died of Cancer... money can't give you a life of happiness just moments that don't last.
In my 44 years on this planet I have learned that being true to yourself, finding loving friends and family (even if your real family sucks, you can go make a new one) , living life on your terms and not at the expectations of others and society, when you can do that you can start to find the road to happiness.
Sometimes to do that, it means walking away from people, ending relationships, being selfish and being okay with being alone for a while. The world is an amazing place once you start to live it on your own terms. I also think, sometimes we have to be sad , so we can truly feel the good times.