Learning Trading System

So I recently wanted to go deeper into TF2 and learn the process of trading & crafting (I use to just buy keys only). I was told at first about buds and stuff like that but I'm still kind of confused on how it works.

For example, my Team Captain hat is 8 buds and a Key is 2.33. Does that mean I can trade my team captain for about like 3 keys?

I'm really confused about this I'd be happy if someone could give me some help :/

Keys are 2.77 refined approx. Which is 2 ref + 2 rec + 1 scrap. Or $1.20-$1.25
Buds are 27-28 keys or $30-$35, which means your team captain is 216-224 keys. Or $240-$270 ish.