There is a particularly good reason why the free course in how to be a successful freelancer won't teach you how to be a successful freelancer: If it did then there'd be no reason to buy the paid course.
They ought to be more clear that you're about to spend time on something that they know won't do what it says it does.
Paid yoga classes _cannot_ work. If free yoga lessons were available on YouTube, then people wouldn't buy the paid ones.
Paid water _cannot_ work. If free water was available in your faucet, then people wouldn't buy the bottled kind.
Paying for print versions of Shakespeare _cannot_ work. If free versions are available on project Gutenberg, then people wouldn't pay for it.
Ever think there may be varying levels of success, and the free week-long version gets you the basics (I can touch my toes, Yoga success!), but not yet an expert? Just like every other field of human activity?
It's worked really well. People love the free course, and those who want a more tactics and accountability buy the full course.
If the free course is nothing but the "sizzle" and a giant pitch for something paid, that's a problem. You're probably not going to get many sales for your paid course, and no one's going to refer others to the free course.
But if it's valuable independently of the premium course, and allows the reader to determine if it makes sense to go pro, then it's a win-win for all involved. At the end of my course, I ask people to reply back with what they got out of the free course and what they plan on changing as a result of it — I get a fair amount of awesome responses (which turn out to be great testimonials) from this last email: http://i.glui.me/1A3VNtx
(Brennan, feel free to use as testimonial / ask me to elaborate.)