You will find not only CD's and DVD's here, but also musical instruments.
Buy.com nearly always has a sale or a few coupons on special. On the Buy.com Coupon page also look for DVD specific coupons and sales.
A&E.com/The History Channel offers unique DVD's featuring their series and movies. A&E.com/The History Channel Coupons are not always regular, but when they have a DVD sale their prices can drop to $5, so set your alerts!
For musical instruments, Wood, Wind, & Brass Coupons page almost alwyas offers free shipping. The more electronically inclined InstrumentPro Coupons page carries more regular coupons while Muscian's Friend Coupons page has more regular closeouts.