What is the difference between danke schön and vielen Dank and besten Dank and herzlichen Dank ?Feel free to just provide example sentences.

First of all they are all kind of interchangeably. I use "Dankeschön" and "Vielen Dank" in the same situation. That could be for example when I say thanks for my change after I bought something. But also when I thank friends for whatever. "Besten Dank" and "Herzlichen Dank" I wouldn't use when I got my change but with friends etc. "Herzlichen Dank" maybe is a bit more formal. Also this one can be used ironically like "Na, herzlichen Dank auch" or "Na, schönen Dank auch." Besten Dank I personally never use but hear a lot on a daily basis when the other person tries to be less formal, like the electrician that just fixed something in my house and asks me to take out the fuse or something. I'd like to add also: "Danke", "Danke sehr" and "Haben Sie vielen Dank." as alternatives. "Danke" = shorter and maybe a bit more informal. "Danke sehr" ist 100% interchangeable with "Danke schön/Dankeschön" and the last one is really a good choice when being formal (thanking your professor etc.).
Hope I could help.