m_hui, Check out this site for various online coupons. May I recommend you that you see if it is available at Overstock.com, they offer very inexpensive, prompt shipping and oftentimes they beat Amazon and & B&N prices. The site below has a coupon code for first time buyer's to receive $5 off a $10 or more purchase, there are also Amazon coupons avail there too.
Hope this helps..
http://www.techbargains.com/coupons.cfm