Bestbuy offers Dell - USB Slim DVD+/- RW Drive - Plug and Play - DW316 - Black for $19.99 (orig. $39.99) with free store pickup.

Product Description:
Burn DVDs and CDs with this Dell USB DVD/RW drive. Plug it into your computer's USB port to play and burn discs or to load new software onto the hard drive. This slim Dell USB DVD/RW drive fits into a tote bag, and it draws power directly from the computer's USB port for hassle-free operation. 

• Multiformat support
  For CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-R, DVD-RAM, DVD-RW, DVD+RW, DVD+R, DVD+R DL, DVD-R DL, M-DISC media.
• 8x maximum DVD+R and DVD-R write speed
  For fast disc burning.
• 8x maximum DVD+RW rewrite speed
  6x maximum DVD-RW rewrite speed.
• 0.75MB cache buffer and Automatic Buffer Under Run Error Protection
  Help eliminate errors for smooth disc burns.
• High-speed USB 2.0 interface
  For fast, reliable operation.