I'll start by saying that, "Money can buy happiness". It might not be exactly as what you think it is though. It's not using money to buy things for the reasons of impressing others the way to achieve happiness, or trying to bribe people to complement your ends, or any of the like. It's actually a different type of utilizing money. It's buying something that makes other people happy, which inherently reciprocates the joy to the buyer. This method of allocating money is a simple form of "giving".
Money gives you an opportunity to give. Once you use it for this purpose, you'll achieve fruitful results in many aspects of your life. If you think haven't experienced this yet, try to remember an instance in your life when you have given something without expecting anything in return. It is highly probable that you used your own money or resources to such act. You may have felt bliss immediately right after the act of giving. This phenomenon has been fortified by many recent studies, and probably the reason why the saying, "To give is to receive," has been everlasting.
We were always taught that pursuing money brings nothing good. Now is the right time to question this belief. Should you not easily consider in any quotes or beliefs you encounter? Buddha answered: "Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense".
In my point of view, all quotes originated from someone who reached a certain deeper realization, insight, or moment of transcendence. For example, the quote "money can't buy happiness" holds true to some but not everyone. If you are still struggling with money and in all honesty you feel glad or secure having money, then money is your happiness.
One should consider who said the quote. Perhaps people who have reached the top of the world and had all the riches and gold may have said that money cant buy happiness. That's fine, because it holds true to them. Unfortunately, unless you reach the same level of realization or experience, you may not hold that statement as true. You have to achieve or reach a certain point of realization similar to the person who made the quote. This is also the reason why quotes are always "original". In Philosophy, the moment one reaches and stated something about it, that remains true and unique to him or her - thus, creating an original quote from that person.
Going back, I assume you've heard that money is the source of all evil. There's actually a revision for that: "The lack of money is the source of evil." Look at everywhere. People kill or inflict pain to get somebody else's resources. People have greed because they lack money. People even lie to get money. Abundance of money and financial stability will help you get rid these negative desires or acts.
Though there's still a problem with this revised quote. Saying something to be a source of evil is primarily faulty and out of the question. Only people can do evil things. It's our intent combined with actions that make circumstances evil. Even good things can be turned evil.
What I'm trying to say is use your money wisely. Buy happiness by giving more and sharing your resources. The more you do so, the more you attract positive things in your life. You'll soon realize that you'll never run out of all these positive things, including money.
Cheers to your abundance!