Don't know much about IDS's these days. I see people asking 20k for normal ones. Figured a 15 ^ 50 would be worth a least a little more. 25-30k?
Edit: It's a Req 9 sword.
PC on Clean 15 ^ 50 Icy Dragon Sword
Lord Zado
Arya Nibelrund
IDS have all the same stats, req 9 and 15>50 on every single one. 15-20k is its market price.