The AudioMoth is a relatively inexpensive autonomous recording unit (ARU) that is ideal for citizen science or community-based acoustic monitoring.
It is made by Silicon Labs. It records audible and ultrasonic sound from 8,000 to 384,00 samples per second.
It can be purchased from LabMaker for $74 US or from GroupGets for $49.99 US during campaigns that take place several times per year.