I used 100 reputation to create a bounty on a question, but this put my reputation at 41.  I could not comment in any way on the responses I received because my reputation did not allow me to comment.  Either a user should not be allowed to go below 50 when posting a bounty, or the rule should be broken for that post.  I know this is a corner case, but it was very very frustrating as a user who gave reputation to get an answer, when the answer was more on the right track but still not a complete answer to the problem.