it kinda depends on which outfit you want to go with. most people buy a really cheap atasuki coat off the internet and buy a cheapo mask. it looks horrendous.
i would go the route of making your jacket and making it look good. as far as the mask if you cast it or build it up well as make it really look 3d, it will turn out great.
Adelheid (KHR!)- 85% done
Fem!Austrian War Succesion France (Hetalia/Nyotalia)- 10% done
Fem!Izaya (Drrr!)- 90% done
Magent!Teto (Vocaloid)- 95% done