Don't even bother. The cape right now is locked behind people having maxed stats and a twisted bow.(1.2b atm).
Also, very high chance you'll get banned and or scammed attempting to even find someone right at this time. Jagex is monitoring all the capes coming into game, it's still a very rare cape. Less than 40 people have it I'm sure.
Wait until at least 500+ have it.
Edit: Even then, expect to pay well over 200m for this cape when services are being offered. It is very difficult.