One user asked me how he could place a bounty on a question, and I was going to answer that he should look in the help screen. But then I noticed that the bounty help page doesn't say the minimum rep for putting a bounty is 75. This user had more than 50, but less than 75, so naturally he was confused.
Of course there are other pages that do mention the minimum rep needed for starting bounties, but not on the "What is a bounty? How can I start one?" page itself. The page title sounds specific enough to warrant such a mention. It's only one sentence.