The course 'niche' is really healthy at the moment so I like that. I'm not sure what any keyword intent would be behind 'course members' per-say. I think it's likely to be swallowed up as a generic capture domain (like 5Gbooster.com is) rather than an end-user customer facing brand. Having said all that, my estimate is $400, so hopefully more than you paid for it.. only time tells if our predictions are great or rubbish!