Economics is an excellent degree. It has a very high earnings potential- in fact, there is almost no upper limit for earnings! If you are good at what you do, you can become rich very quickly.
That being said, the reason it's so good is because it's a very difficult subject. If you can do it, and can do it well, you can easily become wealthy with a degree in econ. It is very hard, but if you are good with numbers and you can think quickly, it is doable.