I contacted M/Monit support directly about the pricing issue...
When asked if they offer a discount for education:
"Unfortunately no, but for not-for profit organisations we might
donate a license."
But the fact remains that the unlimited license cost is intentionally low at ~$590.
As for free alternative monitoring frameworks, I worked at a DevOps-focused firm that was unaware of Monit's existence, so they ended up writing their own solution. Check it at Github - https://github.com/ZenFire/gaggled
You could also just rely on the free Monit emails and perhaps script around or parse the command-line monit status
output. It's pretty easy to digest...
# monit status
The Monit daemon 5.5 uptime: 1d 20h 32m
System 'xt.brazzers.com'
status Running
monitoring status Monitored
load average [0.96] [0.53] [0.67]
cpu 50.2%us 1.4%sy 2.1%wa
memory usage 5070168 kB [84.7%]
swap usage 0 kB [0.0%]
data collected Fri, 27 Dec 2013 07:06:10
Filesystem 'var'
status Accessible
monitoring status Monitored
permission 755
uid 0
gid 0
filesystem flags 0x1000
block size 4096 B
blocks total 1548176 [6047.6 MB]
blocks free for non superuser 860636 [3361.9 MB] [55.6%]
blocks free total 939279 [3669.1 MB] [60.7%]
inodes total 393216
inodes free 378393 [96.2%]
data collected Fri, 27 Dec 2013 07:06:10
Process 'orca'
status Running
monitoring status Monitored
pid 2720
parent pid 1
uptime 1d 9h 5m
children 0
memory kilobytes 439120
memory kilobytes total 439120
memory percent 7.3%
memory percent total 7.3%
cpu percent 49.9%
cpu percent total 49.9%
data collected Fri, 27 Dec 2013 07:06:10