I was at a local Target last night and saw two Swiss Gear backpacks on clearance on the back wall near the luggage section. Here are the links to these backpacks on Target.com (prices are higher online) -
Black Backpack ($15 in store) [target.com]
Gray Backpack ($30 in store) [target.com]
Here is the link to Brickseek so you can check prices and availability in store -
Black Backpack DCPI - 069-10-0099
Gray Backpack DCPI - 069-10-0281
I'm not sure how to create direct links to Brickseek using the DCPI's, but maybe someone could do that.
Note that both backpacks show out of stock on Brickseek at the Target store I was in, but both were there at the clearance prices above.
: People are reporting that they have found the gray backpack for as little as $9.00. Once again, YMMV.