I don’t know. But I heard that many people spend a lot of money for buying just small amount of happiness. It may mean that happiness is buy-able. However, it is wondered that why they spend so a lot of money for buying it. Happiness must be very expensive. On the contrary, I also heard some people said that they didn’t need to spend any money but they can be happy or got full of happiness. What is the point of differences?
In the concept of Buddhism, there is no bliss or happiness. The lord Buddha had declared what he found was only suffering existed. Most people in the world are suffering from passion attacking their mind all the time. Whenever, they can get rid of passion, they will be happy or obtain happiness instantly.
In the actual world, most people may understand what we call happiness may be something like this, when we get suffering because of our desire of anything. When we spend some money (may be big or small amount of money) to feed our passion, our desire has been fed temporarily and reduced, this is called happiness. Actually, suffering still exist as long as it hasn’t been got rid completely from our mind. The way to be happiness is not necessary to use any money.
Whether happiness is buy-able or not. The answer can be both YES and NO (or not necessary). Small amount and un-sustainable happiness can be buy-able. But for sustainable happiness, it is not necessary (or NO) to buy but do it by yourself.