instead of selecting a specific room, you boot a gty ( which is usually priced lower than any cabin) which promises that you will receive a cabin in that class or higher. For example, on my last cruise, I booked a gty inside room cat n and paid $500 pp. I ended up with a cat FF outside room was was going for about $650 pp. so I paid $500 for a $650 cabin. now of couse there is always the chance that you end up with the lowest level cabin on the ship but then again, you also paid the lowest price.