I once stumbled upon a question, and I wanted to be a bit charitable. So I opened up the bounty menu, and it says that the minimum is 50 points. I don't want to give so much of my reputation; I only want to give 15 or 25 points, something that attracts people to the question but doesn't require a lot of sacrifice. Why can't the minimum be something lower for those who don't have as much rep?
An upvote is +10 reputation. An accept tick is +15 reputation. Both of them together is +25 reputation.
Making bounties that "cheap" would essentially make them extra upvotes/accepts. That's not what bounties are for. Bounties are to reward exceptional content and draw attention to a question that needs additional attention - resulting in users going out of their way to answer a question that would, otherwise, be left to rot.