The course description sounds essentially the same as just following HOWTOs (which is how I taught myself the basic tools involved in sysadmin-ing many years ago). Just follow these old tutorials and save $20.
There are certainly tons of free resources out there, but I'm busy enough that $1/day for 20 days of emails with directed tutorials is more than worth it. Those howto's look like a great resource for more detailed (and varied) info, but I just need someone to guide me (and gently prod me) through the basics.
It does but many people lack the confidence to undertake something like learning a daunting new task on their own, having a class with a guiding direction from people smarter than you is always a good thing.