Anytime you see any kind of sales pitch or advertising offering or mentioning the words, FREE, CHEAP FAST, QUICK, INSTANT RESULTS, EASY or any similar words. Walk away.
Any decent SEO activities worth pursuing are those that are not straight forward, requires effort and some level of manual input. Hence why people pay good SEO consultants or agencies decent sums of money to do.
There is no quick fix, easy solution, and the techniques that can give you results almost immediately are surely those that would get you banned or penalised shortly after.
If you are delving into the world of SEO, my strongest recommendation would be to read up about it online first. MOZ has a decent free guide to SEO. Once you've read the basics, you'll realise exactly what I mean about the above claims to "quick result seo".
No tool can completely do you SEO. Tools out there like Yoast are there to make life easier when tackling the mamouth task of SEO.
Content is very important as many people have said before. To be precise, don't write anything for the sake of it, and certainly don't copy others. Write about things relevant to your website/business, make it worth a read. If you wrote and article, and it isn't the type of thing you would post to your friends, then it's not worth writing.
To protect yourself for being ripped off, you simply have to first learn the basics of how SEO works.