Buy.com has (4-Pack) PhD Mechanical Pencil, Retractable, .5mm Lead, Gold/Black Barrel -Papermate/Sanford Ink Company - Bulk Packaging – 67004 - $5.99 + free shipping.
Papermate PhD Mechanical Pencil, Black with Gold Detailing and Pocket Clip. Comfortable triangular grip provides the highest degree of writing comfort - it's so comfortable that it is endorsed by the American Physical Therapy Association. A shock-absorbing tip reduces lead breakage while the spring-tip permits continuous writing. Tuff Stuff Jumbo-Twist eraser advances with a twist. Uses 0.5mm lead which is both retractable and refillable.
Tech Specs
0.5mm Lead
Retractable and refillable
Tuff Stuff Jumbo-Twist eraser advances with a twist
Comfortable triangular grip provides the highest degree of writing comfort
Black Barrel with Gold Detailing and Pocket Clip
Shock-absorbing tip reduces lead breakage.
Spring-tip permits continuous writing.
Tuff Stuff Jumbo-Twist eraser advances with a twist.
Endorsed by the American Physical Therapy Association.
Retractable and refillable.
(4-Pack) PhD Mechanical Pencil, Retractable $5.99 FS 
