There could be all sorts of reasons for doing what at first glance appears impractical. Somebody wanting to sell off a number of dvds might well offer any items they consider a 'hard sell' for a nominal amount to increase their chances of selling everything. Somebody might also offer an item for a nominal sum because they want it to go to a good home but aren't aware that mailing lists such as freecycle exist. So, all sorts of reasons but perhaps not well thought through ones.