Yes, both Logstash and Splunk Enterprise offer a Free Trial.
Logstash is designed for Large Enterprises, Medium Business and Small Business.
Splunk Enterprise is designed for Large Enterprises and Medium Business.
Pricing for Logstash Starts at $16/Month whereas for Splunk Enterprise Starts at $150/Month.
Some top alternatives to Logstash includes Elasticsearch, Etlworks Integrator, Splunk Enterprise, Matillion ETL, Fivetran, K3, Datagaps ETL Validator, Etleap, Optimus Mine and ETLrobot.
Some top alternatives to Splunk Enterprise includes Reveal, Sprinkle Data, Data Monkey, Knarr, Iteratively, Splunk Cloud, Easy Insight, dataSights, Squirro Service Insights and Data Suisse.