I am just wondering

Heys! I need your advice, please help. I want to buy Grey's Anatomy Seasons 1-5 DVD Boxset. I searched on the net and found a site named DVDORDERONLINE, it only sells at $56.99. What’s more, all its DVDs are 10% discount these days. I want to buy one, but I don’t whether the site is trustful or not. So I turn to you guys, maybe you can help me. Any thoughts is OK. Thank you!
By the way, its site is www.dvdorderonline.com