As I said here, there are many ways to get better answers for your questions. Bounties are not the only way, in fact, bounties do not always work.
If people are not answering your question, you should engage anyone who did and then attempt to edit your question based on their feedback to be easier to answer.
Then, after you think you have gathered enough extra information (or clarifications) you should edit the question, and it will be bumped to the top of the active page. This means that not only will more people see it, it will also be a better question than it was before.
Make sure to respond to the commenters and answers with the "@" syntax so that they are informed that you have responded.
The Bounty feature was intended as a reward for people who have invested the time to gain the reputation. So it is definitely [by-design] that users with low reputation can not offer a bounty. But there are still ways to get the answers you are looking for without a Bounty