Hi
changzhu - welcome to the 405th!
While some of our members create models for other members for free that is ultimately up the the original creator. While none of them came up with the original concepts they still put a lot of work to bring these game models to life. The one you posted looks like
Timuche 's file and he is selling casts of it. He did a fantastic job don't you think? He deserves to get paid for this great work. Visit his Facebook page Timuche Props and he may be willing to send one to you!