You can see the general payout levels here: http://www.google.com/about/appsecurity/reward-program/ , normally the top payout is about $ 20,000, but the top payout (for Chrome) currently 2 people have been rewarded with $ 60,000. There is an overview of the top payouts though: http://www.chromium.org/Home/chromium-security/hall-of-fame.
Some payouts are $1337 ,$3133.7 or $31336 :P
Microsoft rewards even up to $100.000 for security issues in the latest OS (currently Windows 8.1)