Hey mate,

As far as I know you can learn any style once you achieve rank 7 in either Clothing, Metalworking or Woodworking.

Anyone who has the style can craft it however it is much harder for a low lvl character to find the Style materials used craft rare styles.

Yes, players do farm and sell rare motifs but they seem to go for anywhere between 50-150k. So id suggest just waiting as there are ways to guarantee finding rare motifs once you reach Veteran ranks.

Technically yes you can learn any motif at any level. Assuming you have the skill points and money for it, you could teach a fresh lv 3 every motif if you really wanted to.

If your using the motifs found in-game then your character must reach a certain rank in either the Metalworking, Tailoring or Woodworking crafting passives. What rank is required depends on which motif you wish to learn (Primal is 6, Barbaric is 7, Ancient Elf is 8, Daedric is 9). So if you wanted to learn to craft Daedric as a Clothier then you'd have to invest 9 points into the Tailoring passive. Thankfully once you learn the style for one craft you unlock it for all. So if you want to take up Blacksmithing later, since you already learned Daedric as a Clothier you can now make daedric even at rank one of Metalworking.

If you use the motifs from the crown store then there is no requirement and you can learn the motif at any time.

I think it depends. I purchased barbaric from the crown store and was able to use it at blacksmithing rank 5. I purchased primal from a guild store and I can't even read the book until blacksmithing/clothing/woodworking rank 6. Daedric is rank 9, I believe. It'll say in the description of the book what rank you need.

Be careful cause you can only get the style mats until you hit high level areas either. They are extremely rare in normal areas.