Staples has 50 pack spindles of HP DVD+R and DVD-R media on sale for $5.99. Shipping is free.
http://www.staples.com/HP-50-Pack-4.7GB ... -nr_572988
http://www.staples.com/HP-4.7GB-DVD-R-5 ... -nr_592647
They also have a 50 pack of HP CD-R discs for $4.99
http://www.staples.com/HP-50-Pack-700MB ... uct_555502
I'm pretty sure these discs are made by CMC