With sacks of rice lining our supermarket shelves, it may be surprising to hear that finding rice seed is, likely, the most difficult step in growing rice. The reason being, you must begin with unhulled seeds. That is, the rice grains must be enclosed in their tight, protective hull.
Food rice already has the hull removed and it will become moldy and rot before it grows. If you live in an area that grows rice, like California or the South, you may be able to find it as local agricultural bulk seed. Otherwise, you'll have to ask around.
Some health food stores stock, or can order, rice in the hull. Don't give up! Though it may not be in your area, rice seed is one of the most common commodities on the planet. But, don't wait too long. Soon, very soon, it may be difficult to find any seed at all, that is not genetically altered.