why does my graphics card cost so much?

One answer bitcoin yes bitcoin. 

You may think well I should start mining now.

that is where you are wrong you should pay someone to mine for you.

Clever though it is, the system has weaknesses. One is rapid consolidation. Most mining power today is provided by “pools”, big groups of miners who combine their computing power to increase the chance of winning a reward.

So you just can't win right?

Well, you can but it will be expensive very Very expensive.

You need a supercomputer. 

This is the power of bitcoin.
 Miners now have 13,000 times more combined number-crunching power than the world’s 500 biggest supercomputers.

Well 300,000,000,000,000 supercomputers.