I'll just say this much; for 1 month straight, you could not go anywhere in Germany without seeing TOR posters. They were everywhere. Every German gaming website had a TOR banner up for at least 2 weeks and they had ads in every commercial break on almost every TV channel for 6 weeks. In addition to that they also hired so called viral marketers just for German forums.
Now take a second and think how much that would cost. Just that. Then multiply it by 20, since they utilized this aggressive marketing in more than just one (relatively small) country. 500m is maybe a tad ridiculous, but if you told me 300m was the answer, I wouldn't doubt it too much.