Where can I get a string/duffel/tote bag? (read whole question)?

Depends on where you live and what stores are around. Department stores like Macy's, Saks, etc, will sell this stuff. Look in their purse and luggage section. Also check out a high-end luggage store. For athletic things like Nike, Adidas, etc, go to sporting goods stores; Academy Sports, Sports Authority, ***** Sporting Goods, Finish Line, etc