Newegg has HP Pavilion dv6-6135DX Notebook (refurbished) for $500 with free shipping.
Specs
AMD Quad Core A8-3500M 1.5GHz
6GB DDR3
640GB HDD
15.6" 1366x768 Display
1GB Radeon HD 6750M
Blu-ray ROM
USB 3.0
WiFi N
6-cell Battery
Windows 7 Home Premium