You can't get the Arch Angel set anymore, unless you buy them from someone else. They used to be gotten from Ice Burners, a one time use cash shop item that gives you one random item, could be as good as an arch angel piece, or as worse as a few element stones.
The Arch Angel set were a limited time only event, and its already passed. Also, Ice Burners are also limited, they aren't always available to buy.
For raven, I'd estimate the pieces of the AA set are:
Gloves, boots = 7m-10m ea
Pants, Top = 10m-12m e
Hair = 60m+
Wings = 65m+
Crown = 65m+