Nobody who is readily capable of finding such a flaw --- which probably doesn't exist, but let's stipulate that it does --- would bid as little as $300 an hour for this work.
the idea of finding an fbi-sponsored, 10-year old backdoor in a notoriously secure operating system installed in many government and corporate networks around the world sounded pretty boring to me, but now that there's a whole hundred dollars on the line, i'll surely be working day and night to find it!