Yes, both PagerDuty and Rely.io offer a Free Trial.
PagerDuty is designed for Large Enterprises, Medium Business and Small Business.
Rely.io is designed for Large Enterprises, Small Business, Medium Business and Individuals.
Pricing for PagerDuty Starts at $10 whereas for Rely.io Starts at $20.00per user / month when Billed Yearly.
Some top alternatives to PagerDuty includes Freshservice, xMatters, Opsgenie, VictorOps, YetiCloud, AlertOps, Splunk On-Call, Splunk Enterprise, ServiceNow Customer Service Management, Zenduty and StatusCast Incident Management.
Some top alternatives to Rely.io includes and undefined.