Hi Blason,
If you want to use this for development use or personal use for testing or just using splunk on your own, you can apply for a developer license (50GB/day). It is free but the license will expire after 6 months I believe when you'll just have to renew it.
Otherwise if you know for sure your bind log file will stay under 50MB then yes you can use the free version.
OK - Sorry for late response.
So yes this for personal use but wondering if I can use Machine learning with Splunk Free? Is ML freely available with Splunk Free or do I need to pay license fees?