$200,000 is the cost of the atoms in the fuel. Most of the rest of the $15 million is the cost to get those atoms to the right temperature and pressure when they are stored at a different temperature and pressure, transport those atoms, and put them in the shell. Not to mention the cost of cleaning and coating the fuel tanks to make sure that they are inert and won't react to the fuel (this has to be done on non-reusable rockets too).

This is the typical sleight-of-hand that comes at Musk companies. The atoms in the fuel are cheap, but the process of turning those atoms into usable fuel is very expensive. This is the case for almost all rockets.

The Soyuz is partly cheap to launch because it doesn't need a lot of special fuel handling.