HP KD853PA 20" Laptop Roller Case for $19.99 after this $20 rebate. Shipping is $4.99 for a total of $24.98 shipped. Here is a screenshot for reference.  It features a padded compartment for up to 20" laptops, pneumatic wheels, pull-out backpack straps, accessory pockets and more.  Most places have it for about $39.