I'd just put the $100 into registering/extending the domain and first year budget hosting, and just spend your own time and labor working on SEO for the first few months. While waiting for the ranking results to improve, you can work on building direct traffic through social media, video, forums and comments. It's possible to do short term non-SEO blitz campaigns to create 5k-10k monthly visitors.
After doing this you could recover your money and active efforts by getting approved for CPM or CPC passive monetization programs (several of them require proof your site has X amount in traffic). At a typical payout of $5 per 1,000 impressions, that could mean $50-100 a month in secondary earnings, which you could view as working capital to pay for a more permanent SEO linking campaign.