HR applications are some of the easiest to look for, for comparables.
Gusto has a nice clean page of $6-$12 per employee pricing:
Many HR apps try to get customers to pay for all employees, per employee.
It’s also interesting that apps like Slack and DropBox that want all employees using them have similar pricing.
Once you start pushing $30-$40+ per user or higher, there are tons of successful apps. But most of those seem to only be sold to a subset of all employees.