Hi I am looking to learn more about sales psychology or I don't know how to describe it better. Basically I want to learn how to convince people to buy stuff, subliminal things that work, buying words, best social engineering, how to create good copy writing and so on. I looked around but it seems the internet is FULL of this stuff, and I don't know which ones are really good, so please recommend me anything that you found interesting regarding this. If it's free and can be downloaded, would be awesome. Thanks a lot !