You might also like this list:
It compares the best email marketing software options. There are over 31 of them including the ones you've already mentioned.
That is because good knowledge is worth paying for.
Courses like Distilled U, Moz, etc are the ones you would look at.
Other than that, be careful of those sites that are just trying to rip you off (like what alec mentioned).
I'm Carlo, an Online Marketing Specialist. I believe this is the appropriate place to put my first post?
Anyway, I signed up so I can participate and share my insights on discussions that I could relate to.
I'm also looking forward to learn a lot from the community!